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Chapter 3
Designing for Environmental Stewardship in Construction & Maintenance
3.11. Designing to Minimize Air Quality Problems


Air quality and pollution have been concerns in the United States for many years, especially in metropolitan areas.


3.11.1 Center for Environmental Excellence by AASHTO Air Quality Resources
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AASHTO's Center for Environmental Excellence provides brief summaries of federal air quality requirements applicable to the transportation community including background information on National Air Quality Standards, Developing State Implementation Plans, Emissions Inventory, Control Strategies, Transportation Control Measures, Motor Vehicle Emissions Budget, Sanctions, Conformity, FHWA Resources, EPA Resources, and Links to air quality laws and regulations, guidance and Related Information. Recent Developments are provided as well as Documents and Reports, Success Stories, and Related Links. Most of these air quality resources are focused on the planning process.

The following practices briefly review design measures to promote air quality and congestions mitigation and air quality (CMAQ) and sources of funding.


3.11.2 New England Governors & Eastern Canadian Premiers Greenhouse Gas Reduction Initiatives
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The Conference of New England Governors and Eastern Canadian Premiers (NEG/ECP) adopted Resolution 25-9 on global warming and its impacts on the environment in 2000, "recogniz(ing) that global warming, given its harmful consequences to the environment and the economy, is a joint concern for which a regional approach to strategic action is required." [N] The Conference led to an Action Plan to "reduce the region's emissions of heat-trapping gases and to build the foundation for a longer-term shift to cleaner and more efficient ways of using energy, as well as identifying and adopting adaptive measures." [N] Without the plan, a 30 percent increase in CO 2 emissions is forecast for New England between 2000 and 2020. National CO 2 emissions levels in the U.S. have been growing about 1.1 percent per year based on the U.S. Department of Energy's Energy Information Agency, with the largest emissions increases coming from the transportation sector. [N]

Climate change is affecting governments and DOTs in a variety of ways. At the 2005 TRB meeting, Alaska DOT & Public Facilities reported the substantial increase in problems and expenditures that Maintenance is facing as a result of recent warming trends. Issues identified for New England states include an increase in weather extremes; stresses on estuaries, bays, and wetlands; changes in precipitation rates impacting water supply and food production; multiple stresses on urban areas; and recreation shifts. In addition, the composition of northeastern forests is anticipated to change dramatically, affecting biodiversity and forest industries. In addition to rising sea level and elevated storm surge levels - with associated problems of coastal erosion and saltwater inundation, rising ground-level ozone, warming would likely favor increased mosquito and tick populations, with associated public health as well as recreational impacts.

The NEG/ECP Climate Change Action Plan identifies steps to address those aspects of global warming which the governors decided are within the region's control to influence. Specifically, the action plan includes: [N]

  • Comprehensive and coordinated regional plan for reducing greenhouse gases.
  • Commitment to reach specified reduction targets for the region as a whole.
  • Commitment from each state and provincial jurisdiction to carry on its own planning for climate change gas reductions, with a coordinated process that includes disclosure of our progress, and a sharing of information including case studies of how various programs are working.
  • Plan for the adaptation of the region's economic resource base and physical infrastructure to address the consequences of climate change.
  • Public education and outreach effort to ensure that the region's citizens continue to be educated about global warming and climate change in order to better protect the earth's natural climatic systems and natural environment.

The plan works within the context of other regional objectives, including:

  • Reducing other pollutant emissions that threaten human health and the natural environment.
  • Maintaining a reliable supply of reasonably priced energy within our region.
  • Reducing dependence on energy imports to the region, thereby keeping energy dollars in our regional economy.
  • Reducing our collective vulnerability to energy price shocks.
  • Providing ‘early adoption' opportunities to enhance the competitive advantage of our region's technology industries.

Some of the opportunities to promote greenhouse gas reductions and appropriate adaptation measures while meeting other governmental goals included:

  • Shifting to less polluting energy resources.
  • Maximizing the efficiency and effectiveness of energy conversion, transport, and consumption within the region.
  • Encouraging and aggressively promoting new technologies which reduce the use of fossil fuels, thus reducing carbon emissions.
  • Taking actions to maintain a greater share of the region's energy dollars in the regional economy leading to more productive reinvestment.
  • Taking actions to support agriculture, fisheries, aquaculture, timber, and other natural resource-based economic sectors to adapt to the climate impacts already being felt.
  • Encouraging similar sensible action by fellow states/provinces and federal governments.
  • Designing and building any new infrastructure to minimize the impacts of climate changes that are likely to occur, based on the extended residence time of gases already released into our atmosphere, and may occur due to inadequate greenhouse gas emission reductions elsewhere.
  • Preserving green spaces, including forests and farm lands.
  • Creating new jobs in the area of energy efficiency and renewables.
  • Contributing to the long-term economic and environmental sustainability and human health and safety of the states and provinces.

The New England governors and Eastern Canadian premiers recognized the following principles as guidelines for action on climate change in the region.

  • The need to identify constructive measures to reduce energy and non-energy related GHG emissions wherever possible, such as to: a) shift to lower and zero carbon energy sources, wherever economically feasible; and b) implement actions that result in higher efficiency in the transportation of passengers and goods.
  • Actions which will support and develop the states' and provinces' economy (so-called "no regrets" measures), when compared to other possible actions, and compared to the cost of inaction, including to: a) be cognizant of the energy supply needs of our region and find constructive measures with regional energy reliability in mind; and b) involve all segments of society - government, business, and citizens - in contributing to reductions in greenhouse gas emissions.
  • The need to foster long-term environmental and economic sustainability, in order to favor economic growth while decreasing total emissions of carbon and other climate change gases, such that states and provinces may: a) explore ways to adapt to the already changing climate, to take advantage of any benefits that might come from these changes, and to adapt our infrastructure and natural resource base accordingly; and b) to explore ways to adapt to climate change in ways that do not increase the production of greenhouse gases in the process, and to be mindful of the health and safety of citizens.
  • The need to work with our federal governments to seek additional solutions that can be addressed at a national level including emission standards, grant programs, and cooperative agreements. There is also a need to work with federal counterparts to improve the energy efficiency of vehicles for sale to the public.

The Conference's goals are as follows:

  • Short-term Goal: Reduce regional GHG emissions to 1990 emissions by 2010.
  • Mid-term Goal: Reduce regional GHG emissions by at least 10 percent below 1990 emissions by 2020, and establish an iterative five-year process, commencing in 2005, to adjust the goals if necessary and set future emissions reduction goals.
  • Long-term Goal: Reduce regional GHG emissions sufficiently to eliminate any dangerous threat to the climate; current science suggests this will require reductions of 75 - 85 percent below current levels.

Action items include the following:

  • Jurisdictions will establish a standardized inventory beginning with their 1990 GHG emissions levels, reported every three years. The process of creating jurisdictional level inventories of existing emissions will assist jurisdictions in the identification of specific measures that will reduce greenhouse gas emissions. A full understanding of the present circumstances and a complete assessment of opportunities for action, in all sectors of the economy, are essential for states and provinces to address climate change issues effectively.
  • Each jurisdiction will create plan, programs, and policies articulating measures to achieve GHG reductions in view of the regional short and mid-term targets. Jurisdictions will report to the NEG/ECP annually on progress made regionally, recommend items for joint action and develop specific task forces to coordinate projects, review progress towards meeting GHG objectives, and produce an updated plan every three years, monitor the results of the actions and policies and share information on their effectiveness.
  • Through promotion of public awareness, by 2005 the plan aims for the public in the region to be aware of the problems and the impacts of climate change and what actions they can take at home and at work to reduce the release of greenhouse gases, as well as adaptive measures they can undertake. This effort encouraged dialogue among traditional conservation organizations, land managers, natural resource-based industries, recreational industries, major energy users, non-government organizations (NGOs) and interested citizens as to the implications of climate change.
  • The region will reduce end-use emissions of GHGs through improved energy efficiency and lower carbon fuels within the public sector by 25 percent by 2012, as measured from an established baseline. As the plan maintains that demonstrating energy efficiency, clean energy technologies and sustainable practices should be a fundamental task of government, the plan seeks to implement public sector energy reduction programs, including to institute policies to encourage the purchase of the most fuel-efficient vehicle available for each type of use and educate government employees about the specific operational changes they can undertake to reduce greenhouse gases and reduce fuel use. Examples include:
    • Promoting carpooling incentive programs and/or telecommuting policies for government employees
    • Educating building managers on measures to improve efficiency in heating, cooling, and lighting
    • Providing office managers with information regarding energy-efficient office products and equipment.
    • Establishing policies that all state and provincial expenditures related to energy conservation and efficiency, having simple payback periods of ten years or less, will be adopted whenever feasible.
    • Establishing jurisdictional policies on sustainable building design to be applied to all state/provincial construction and renovation projects where such practices are feasible and cost-effective. Sustainable design practices include:
      • using recycled, energy-efficient, and less toxic materials
      • day lighting and other energy saving measures
      • piloting on-site renewable energy projects
      • separating and recycling construction and demolition debris.
    • Creating a regional market for "Environmentally Preferable Products" (EPPs) by requiring their use at all state/provincial facilities. EPPs include materials with recycled content, those that minimize generation of toxic materials, and products otherwise designed to minimize the environmental impact from manufacture to disposal.
    • Create a regional clearinghouse of "best practices" for the operation and management of public facilities so jurisdictions can share and benefit from each other's experiences.
  • By 2025, increase the amount of energy saved through conservation programs by 20 percent (as measured in tons of greenhouse gas emissions) within the region , using programs designed to encourage residential, commercial, industrial and institutional energy conservation.
  • Understand and improve knowledge transfer on the impacts and costs of climate change, including documenting impacts, exchanging information and research, developing modeling capacities, identifying areas most susceptible to catastrophic events and proposing adaptation and mitigation strategies.
  • Expand the use of land conservation techniques such as conservation restrictions to protect green spaces, forest resources and soil carbon. Increase native tree planting programs, improving maintenance of existing trees, and monitoring the carbon uptake and release of planting programs over time to establish a better understanding of the long-term carbon benefits of such programs. Improve development practices to limit the destruction of existing trees and encourage/require the planting of native replacement trees when changing the nature of land use. Adding trees, where feasible, to urban areas to reduce heat island effect, thereby reducing the need for nearby building air conditioning.
  • Slow the growth rate of transportation emissions in the near future, to better understand the impacts of transportation programs and projects on overall emissions, and to seek ways to reduce these emissions. Work with federal officials to improve the energy efficiency of vehicles for sale to the public.
    • Promote the shift to higher efficiency vehicles, lower carbon fuels and advanced technologies through the use of incentives and education.
    • Disclose GHG emission impacts from new publicly-funded passenger and freight transportation projects and alternatives.
    • Promote compact development and transit/pedestrian development and other "smart growth" measures to encourage local communities to consider the energy impacts of development and infrastructure construction.
    • Undertake programs designed to manage and reduce transportation demand in communities.
    • Enhance mass transit infrastructure, intermodal connections, optimizing existing services and, where feasible, boosting ridership.
    • Encourage shifts to lower-carbon fuels and advanced vehicle technologies for all transit services.
    • Examine opportunities in freight transportation that would improve the energy efficiency of the movement of goods across the regions.
    • Support the development of inter-connected regional, state, provincial, and local greenway and bicycle/pedestrian pathway systems to promote non-fossil transportation alternatives.

State DOTs in the Northeast are supporting the effort through inventory, electricity and space heating reductions, employee commuting, public involvement processes, and looking beyond operations. Some states are developing tools to measure the GHG emissions of transportation projects. The following have been reported as under consideration by DOTs in the region:

  • Centralized vehicle fleets that include:
    • Consistent collection and monitoring of fuel use and emissions data
    • Rightsizing (using the right size and type of vehicle for the job)
    • Timely and consistent maintenance schedules
    • Replacing the use of state employee personal cars for official state business with more fuel efficient and lower emission state fleet vehicles, without increasing the total vehicle miles traveled by employees during pick up and drop off of fleet vehicles and traveling to and from home
  • State contracts requiring the purchase or rental of the most fuel-efficient and lowest emission vehicles in each vehicle class for the state fleet.
  • Establishing the environmental and economic impacts of replacing the use of conventional diesel fuel for the state fleet with biodiesel blends, and beginning replacement when appropriate.
  • Promoting the use of telephone, video, and online conferencing to reduce trips.
  • A single (or compatible) maintenance, parts and equipment contract(s) for state motor vehicles and motorized equipment that require state of the art emissions, fuel efficiency, and overall environmental beneficial technologies and practices.
  • Maintenance procedures for heavy-duty vehicles that promote state of the art emissions control, fuel efficiency, and other environmentally beneficial technologies and practices.
  • Marketing the use of public transit and vanpools (when available), ridesharing, and non-motorized options such as walking and biking while on the job.
  • Establishing and actively promoting shuttle bus/van routes and schedules between key state facility destinations
  • Expanding existing vehicle anti-idling education campaigns to state-owned facilities.
  • Locating new state facilities and services (such as copy centers, daycare, etc.) within close proximity and within mixed use growth centers, thus facilitating employee walking and biking while making short on the job trips.


3.11.3 Promoting Carpooling and Transit
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Urban air pollution is a major and continuing concern for transportation agencies. Motor vehicles are a major contributor to this pollution. One possible means of mitigating the pollution caused by motor vehicles is to shift travel to alternate modes. Some states are very active in promoting alternate modes; in other, especially rural, states promotion of mode switching is minimal. Arizona DOT has a research project underway, with results due in late 2004, to compile practices in use by other state DOTs. [N] DOT and MPO carpool and transit promotion activities are often funded under the CMAQ program.

Georgia DOT HOV Land Promotion

Georgia Department of Transportation (GDOT) in the Atlanta area used CMAQ funds to focus on HOV lanes and park and ride lots over lanes widening and another beltway. [N] GDOT conducted a statewide kickoff of the media campaign to increase awareness of HOV lanes under construction in Gwinnett County, and to increase use of the existing HOV lanes and metrorail. The event attracted significant media coverage, including three Atlanta television stations. GDOT also ran radio ads on several stations throughout the year and has a campaign highlighting the need for and benefits of carpooling. [N]

Virginia DOT Commuter Choice Program

The Virginia Department of Transportation has been praised by the EPA and the USDOT for its "Commuter Choice" program and contribution to improving air quality. VDOT has offered its employees bus, vanpool and carpool options since 1993 with its own "Commuter Incentive Program" (CIP), and is not only Richmond's largest employer with such a program, but also the employer with the highest commuter participation. VDOT reports that the program is a very successful recruitment factor. To illustrate the benefits of joining its program, the EPA estimates that an employer with 1,000 employees could help take 175 cars off the road, which would save 44,000 gallons of fuel per year and reduce global warming emissions by 420 metric tons. The same employer also could reduce its parking expenses by $70,000 and save participating employees $13,000 in taxes and $160,000 in fuel, parking, and vehicle costs every year - employees pay no federal income tax or payroll tax on commuter benefits. For VDOT's headquarters office, it's estimated that the program saves more than 93,500 gallons of vehicle fuel per year, and reduces air pollution by 4.25 metric tons of volatile organic compounds, 4.25 metric tons of nitrogen oxides, and 31 tons of carbon monoxide. VDOT's CIP has grown from 196 participants in August 1993 to 373 participants in 2003 - 27 percent of its headquarters office workforce (69 vanpoolers, 262 bus riders and 42 carpoolers) - at an annual cost to VDOT of $151,680. Eight percent (110 employees) of its Northern Virginia work force participate (82 vanpool, 11 bus, 7 Metro train riders, and 10 Metro/bus) at an annual cost of $124,080. [N]

Transit Promotion Activities

NC DOT is studying feasibility of intercity rail from eastern to western NC, through the state's Triad of largest cities. [N] Transit promotion activities of other state DOTs can be found through links to these sections online.


3.11.4 Promoting Telecommuting
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The U.S. Congress's 1999 National Air Quality and Telecommuting Act (H.R. 2094) set up a pilot program in five metropolitan areas - Denver; Washington, DC; Los Angeles, Houston, and Philadelphia - that would study the feasibility of addressing air quality concerns through telecommuting. The pilot "e-commute" program ran from mid-2001 through early 2004, at which time scholars conducted an in-depth analysis of data drawn from participants' reports as part of a larger report to U.S. EPA.

A December 2004 investigation of Telecommuting and Emissions Reductions looked at reports from 535 employees working in approximately 50 different companies in five cities over a two-and-a-half year period, tracking employees over time and that the frequency of reporting. The authors estimated that a 25-ton per year reduction in volatile organic compounds could be achieved in a given metropolitan area with approximately 4,500 telecommuters working at home, on average, 1.8 days per week. [N]


3.11.5 Bicycling Promotion Activities
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Bicycling promotion has begun to be incorporated into DOT planning and design, and efforts to improve air quality in some cases. FHWA has Design Guidance for Accommodating Bicycle and Pedestrian Travel and a US DOT Policy Statement Integrating Bicycling and Walking into Transportation Infrastructure, which also asks DOTs to "be committed to taking some or all of the actions listed below as appropriate for their situation." [N]

  • Define the exceptional circumstances in which facilities for bicyclists and pedestrians will NOT be required in all transportation projects.
  • Adopt new manuals, or amend existing manuals, covering the geometric design of streets, the development of roadside safety facilities, and design of bridges and their approaches so that they comprehensively address the development of bicycle and pedestrian facilities as an integral element of the design of all new and reconstructed roadways.
  • Adopt stand-alone bicycle and pedestrian facility design manuals as an interim step towards the adoption of new typical sections or manuals covering the design of streets and highways.
  • Initiate an intensive re-tooling and re-education of transportation planners and engineers to make them conversant with the new information required to accommodate bicyclists and pedestrians. Training should be made available for, if not required of, agency traffic engineers and consultants who perform work in this field.

The Design Guidance also offers sections on:

Virginia DOT Bicycle Facility Guidelines

Virginia DOT's Bicycle Facilities Guidelines contain the agency's Policy on Participation in the Development of Bicycle, VDOT Bicycle Facility Participation Guidelines, AASHTO's guidance, and the agency's guidelines on Selecting Roadway Design Treatments to Accommodate Bicycles.

NCDOT Commitment to Integrating Bicycle and Walking into Transportation System and Long-Range Plan

The NC Board of Transportation adopted Bicycling & Walking in North Carolina, a Critical Part of the Transportation System in 2000. Although NCDOT already incorporated bicycle and pedestrian elements - including bike lanes and sidewalks - into many of its highway projects, this resolution demonstrated NCDOT's further strong commitment to integrating these elements into its long-range transportation system. The resolution also encourages cities and towns across the state to make bicycling and pedestrian improvements an integral part of their transportation planning and programming. In addition to offering the potential for cleaner air, NCDOT noted that: [N]

  • Increasing bicycling and walking offers the potential for cleaner air, healthier people, reduced congestion, more liveable communities, and more efficient use of road space and resources.
  • Cashes involving bicyclists and pedestrians represent more than 14 percent of the nation's traffic fatalities.
  • FHWA in its policy statement "Guidance on the Bicycle and Pedestrian Provisions of the Federal-Aid Program" urges states to include bicycle and pedestrian accommodations in its programmed highway projects.
  • Bicycle and pedestrian projects and programs are eligible for funding from almost all of the major Federal-aid funding programs.
  • TEA-21 calls for the mainstreaming of bicycle and pedestrian projects into the planning, design and operation of our Nation's transportation system.

Following the resolution, a team of NCDOT personnel reviewed and implemented guidelines to successfully integrate bicycle and pedestrian planning into the daily operations of the department. The effort builds on NCDOT's longstanding commitments in this area. In 1978, NCDOT adopted the nation's most comprehensive set of bicycle policies in response to enabling legislation in the Bicycle and Bikeways Act of 1974. These policies were unique at that time in that they detailed how the state DOT would institutionalize bicycle provisions into everyday departmental operating functions. They declared "bicycle transportation to be an integral part of the comprehensive transportation system in North Carolina" and formalized the inclusion of bicycle provisions in highway construction projects. In 1991, the policy document was updated to clarify responsibilities regarding the provision of bicycle facilities upon and along the 77,000-mile state-maintained highway system. The newer policy details guidelines for planning, design, construction, maintenance, and operations pertaining to bicycle facilities and accommodations. All bicycle improvements undertaken by the NCDOT are based upon the NCDOT Bicycle Policy. According to that policy, the Board of Transportation found that bicycling is a bona fide highway purpose subject to the same rights and responsibilities and eligible for the same considerations as other highway purposes and endorsed the concept of providing bicycle transportation facilities within the rights-of-way of highways as appropriate. The following practices and guidelines were outlined: [N]

Planning and Design
  • The intent to include planning for bicycle facilities within new highway construction and improvement projects is to be noted in the Transportation Improvement Program.
  • During the thoroughfare planning process, bicycle usage shall be presumed to exist along certain corridors (e.g., between residential developments, schools, businesses and recreational areas). Within the project planning process, each project shall have a documented finding with regard to existing or future bicycling needs. In order to use available funds efficiently, each finding shall include measures of cost-effectiveness and safety-effectiveness of any proposed bicycle facility.
  • If bicycle usage is shown likely to be significant, and it is not prohibited, and there are positive cost-effective and safety-effective findings; then, plans for and designs of highway construction projects along new corridors, and for improvement projects along existing highways, shall include provisions for bicycle facilities (e.g., bike routes, bike lanes, bike paths, paved shoulders, wide outside lanes, bike trails) and secondary bicycle facilities (traffic control, parking, information devices, etc.).
  • Federally funded new bridges, grade separated interchanges, tunnels, and viaducts, and their improvements, shall be designed to provide safe access to bicycles, pursuant to the policies of FHWA.
  • Barriers to existing bicycling shall be avoided in the planning and design of highway projects.
  • Although separate bicycle facilities (e.g., bike paths, bike trails) are useful under some conditions and can have great value for exclusively recreational purposes, incorporation of on road bicycle facilities (e.g., bicycle lanes, paved shoulders) in highway projects are preferred for safety reasons over separate bicycle facilities parallel to major roadways. Secondary complementary bicycle facilities (e.g., traffic control, parking, information devices, etc.) should be designed to be within highway rights-of-way.
  • Technical assistance shall be provided in the planning and design of alternative transportation uses, including bicycling, for abandoned railroad rights-of way. This assistance would be pursuant to the National Trails act Amendment of 1983, and the resultant national Rails to Trails program, as will the Railway Revitalization Act of 1975.
  • Wherever appropriate, bicycle facilities shall be integrated into the study, planning, design, and implementation of state funded transportation projects involving air, rail, and marine transportation, and public parking facilities.
  • The development of new and improved bicycle control and information signs is encouraged for the increased safety of all highway users.
  • The development of bicycle demonstration projects which foster innovations in planning, design, construction, and maintenance is encouraged.
  • Paved shoulders shall be encouraged as appropriate along highways for the safety of all highway users, and should be designed to accommodate bicycle traffic.
  • Environmental Documents/Planning Studies for transportation projects shall evaluate the potential use of the facility by bicyclists and determine whether special bicycle facility design is appropriate.
  • Local input and advice shall be sought, to the degree practicable, during the planning stage and in advance of the final design of roadway improvements to ensure appropriate consideration of bicycling needs, if significant.
  • On highways where bicycle facilities exist, (bike paths, bike lanes, bike routes, paved shoulders, wide curb lanes, etc.), new highway improvements shall be planned and implemented to maintain the level of existing safety for bicyclists.
  • Any new or improved highway project designed and constructed within a public-use transportation corridor with private funding shall include the same bicycle facility considerations as if the project had been funded with public funds. In private transportation projects (including parking facilities), where state funding or Department approval is not involved, the same guidelines and standards for providing bicycle facilities should be encouraged.
  • Bicycle facilities shall be constructed, and bicycle compatibility shall be provided for, in accordance with adopted Design Guidelines for Bicycle Facilities and with guidelines of the American Association of State Highway and Transportation Officials.
  • Rumble strips (raised traffic bars), asphalt concrete dikes, reflectors, and other such surface alterations, where installed, shall be placed in a manner as not to present hazards to bicyclists where bicycle use exists or is likely to exist. Rumble strips shall not be extended across shoulder or other areas intended for bicycle travel.
  • During restriping operations, motor vehicle traffic lanes may be narrowed to allow for wider curb lanes.
  • State and federally funded and built bicycle facilities within the state right-of-way are to be maintained to the same degree as the state highway system.
  • In the maintenance, repair, and resurfacing of highways, bridges, and other transportation facilities, and in the installation of utilities or other structures, nothing shall be done to diminish 1.77+45 existing bicycle compatibility.
  • Rough road surfaces which are acceptable to motor vehicle traffic may be unsuitable for bicycle traffic, and special consideration may be necessary for highways with significant bicycle usage.
  • For any state-funded bicycle project not constructed on state right-of-way, a maintenance agreement stating that maintenance shall be the total responsibility of the local government sponsor shall be negotiated between the Department and the local government sponsor.
  • Pot-holes, edge erosion, debris, etc., are special problems for bicyclists, and their elimination should be a part of each Division's maintenance program. On identified bicycle facilities, the bike lanes and paths should be routinely swept and cleared of grass intrusion, undertaken within the discretion and capabilities of Division forces.
  • Operations and activities on the state highway system and bicycle facilities shall be conducted in a manner conducive to bicycle safety.
  • A bicyclist has the right to travel at a speed less than that of the normal motor vehicle traffic. In exercising this right, the bicyclist shall also be responsible to drive his/her vehicle safely, with due consideration to the rights of the other motor vehicle operators and bicyclists and in compliance with the motor vehicle laws of North Carolina.
  • On a case by case basis, the paved shoulders of those portions of the state's fully controlled access highways may be studied and considered as an exception for usage by bicyclists where adjacent highways do not exist or are more dangerous for bicycling. Pursuant to federal highway policy, usage by bicyclists must receive prior approval by the Board of Transportation for each specific segment for which such usage is deemed appropriate, and those segments shall be appropriately signed for that usage.
  • State, county, and local law enforcement agencies are encouraged to provide specific training for law enforcement personnel with regard to bicycling.
  • The use of approved safety helmets by all bicyclists is encouraged.
  • It is the policy of the Board of Transportation that secure and adequate bicycle parking facilities shall be provided wherever practicable and warranted in the design and construction of all state-funded buildings, parks, and recreational facilities.

Maryland DOT Bicycle Safety and Operations Guidelines

In 2002, the Maryland DOT published Guidelines Related to Bicycle Safety and Operations on Roadways in Maryland. The guidelines seek to allow bicyclists to operate, as they feel appropriate, on all roads were they are not specifically prohibited. Among the other guidelines: [N]

  • Wide curb lanes for bicycle use are preferred on all closed section roadways. The width of a wide curb lane typically ranges from 13 to 16 ft, measured from the lane line to the curb face (or the edge line on open section roadways). In situations where 14 ft or more of pavement width exists, the roadway should be striped with a longitudinal white line 11 ft from the rightmost lane line to create either an otherwise unmarked "Bicycle Area", a fully marked and signed Bicycle Lane, or a shoulder.
  • Bicycle Lanes should be one-way facilities and carry bike traffic in the same direction as adjacent motor vehicle traffic. On one-way streets Bicycle Lanes should generally be placed on the right side of the street. (For further commentary on placement of Bicycle Lanes, see page 22 of the AASHTO Guide.)
  • For roadways with no curb and gutter, the minimum width of a Bicycle Lane should be 4 ft. For roadways with curb or guardrail, the recommended Bicycle Lane width is 5 ft from the face of the curb or guardrail to the Bicycle Lane stripe.
  • If parking is permitted, the Bicycle Lane should be placed between the parking area and the travel lane and have a minimum width of 5 ft.
  • Since bicyclists usually tend to ride a distance of 32-40 in. from a curb face, it is very important that the pavement surface in this zone be smooth and free of structures. Drain inlets and utility covers that extend into this area may cause bicyclists to swerve, and have the effect of reducing the usable width of the lane. Where these structures exist, the Bicycle Lane width may need to be adjusted accordingly.

TAC Bicycle Traffic Pavement Marking Guidelines

Updated in December 2004 with expected final completion and approval in 2006, the Transportation Association is producing Bicycle Traffic Pavement Marking Guidelines. Numerous jurisdictions have recognized the need to provide national guidance on the effective use of pavement markings and colored pavements to guide cyclists in many situations, including in shared-use lanes, in contra-flow, two way on one side traffic, and through intersections and interchanges (including roundabouts). Looking at best practices in North America and Europe, the oversight committees noted that pavement markings take many forms and functions and are not always intuitive and easily understood by motor vehicle traffic and cyclists. Furthermore, it seemed that the use of pavement markings has been discretionary, without clear guidelines, numerical evaluation processes or ranking systems to help determine when benefits can be achieved. The project is developing guidelines and recommendations on the design and application of pavement markings for bicycle traffic on Canadian roads. It will provide recommendations on the most effective configuration of pavement markings, use of materials, installation, maintenance and cost, in addition to determining numerical evaluation processes and ranking systems.


3.11.6 ITS Facilitated Air Quality Improvement in Ohio and Kentucky
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In the Cincinnati, OH, metropolitan area the Ohio Department of Transportation and the Kentucky Transportation Cabinet developed the Advanced Regional Traffic Interactive Management and Information System (ARTIMIS) to help with incident and congestion management. Using fiber-optic cable and telephone lines, 80 closed-circuit television cameras and 1,100 loop detectors, installed along 142 kilometers (88 miles) of freeway, relay information about traffic congestion and incidents to a control center. Through 40 changeable message signs, ARTIMIS distributes information on traffic problems and alternate routes from the control center to motorists. The system also includes a traveler advisory telephone service and a motorist assistance program with five service patrol vans. Estimates show that the system saves $15.9 million per year in reduced traffic delays, fuel consumption, and crashes. [N]


3.11.7 Funding for Air Quality Improvement: The Congestion Mitigation & Air Quality Program (CMAQ)
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The most well known program supporting air quality improvement is the Congestion Mitigation and Air Quality Program. In 1990, Congress amended the Clean Air Act (CAA) to bolster America's efforts to attain the National Ambient Air Quality Standards (NAAQS). The amendments required further reductions in the amount of permissible tailpipe emissions, initiated more stringent control measures in areas that still failed to attain the NAAQS (nonattainment areas), and provided for a stronger, more rigorous linkage between transportation and air quality planning. In 1991, Congress adopted the Intermodal Surface Transportation Efficiency Act (ISTEA). This law authorized the CMAQ program, and provided $6.0 billion in funding for surface transportation and other related projects that contribute to air quality improvements and reduce congestion. The CAA amendments, ISTEA and the CMAQ program together were intended to realign the focus of transportation planning toward a more inclusive, environmentally-sensitive, and multimodal approach to addressing transportation problems. The CMAQ program, jointly administered by the FHWA and the Federal Transit Administration (FTA), was reauthorized in 1998 under the Transportation Equity Act for the 21st Century (TEA-21). The TEA-21 CMAQ program provided over $8.1 billion dollars in funds to State DOTs, MPOs, and transit agencies to invest in projects that reduce criteria air pollutants regulated from transportation-related sources over a period of six years (1998-2003).

The percentage of CMAQ funds obligated for transit was higher than that of any other category in FY 1999, the last year for which a report is available. The total CMAQ funds obligated toward transit accounted for 51.6 percent of the total amount of funds obligated nationwide, a 70 percent increase in CMAQ share from FY 1998 (from 30.1 percent to 51.6 percent). Traffic flow improvement projects were the second largest category at 23.3 percent, a 50 percent decrease in CMAQ share from FY 1998. [N]

Comparing findings from almost 140 CMAQ-funded projects, for which actual impacts had been quantified, the study ranked the project types by the cost per pound of combined pollutants reduced as follows: [N]

CMAQ Strategy Cost Per Pound of Emissions Reduced

Inspection and maintenance...............................................$0.95/lb.

Regional rideshare programs .............................................$3.70/lb.

Charges and fees ................................................................$5.15/lb.

Vanpool programs..............................................................$5.25/lb.

Miscellaneous TDM...........................................................$6.25/lb.

Conventional fuel bus replacement....................................$8.05/lb.

Alternative fuel vehicles ....................................................$8.09/lb.

Traffic signalization .........................................................$10.05/lb.

Employer trip reduction ...................................................$11.35/lb.

Conventional transit service upgrades .............................$12.30/lb.

Park-and-ride lots (rideshare and transit).........................$21.50/lb.

Modal subsidies and vouchers .........................................$23.30/lb.

New transit capital systems/vehicles ...............................$33.20/lb.

Bicycle and pedestrian programs .....................................$42.05/lb.

Shuttles, feeders, and paratransit .....................................$43.75/lb.

Freeway/incident management ........................................$51.20/lb.

Alternative fuel buses ......................................................$63.20/lb.

HOV facilities ..................................................................$88.10/lb.

Telework ........................................................................$125.90/lb.

Therefore, among the top 10 strategies, the most cost effective alternative mode strategies are:

  • Regional ridesharing programs (including carpool matching)
  • Pricing programs (including parking pricing and congestion pricing)
  • Vanpool programs
  • Miscellaneous TDM programs (efforts to promote alternative modes)
  • Conventional transit service improvements (new lines, more frequency)
  • Employer trip reduction.

The analysis showed that as a group, traffic flow projects received 33 percent of all funds, but resulted in a cost per pound reduced of $42.70. Rideshare programs accounted for only 4 percent of all funds, yet reduced a pound of emissions for $10.25. Likewise, miscellaneous TDM programs accounted for 3 percent of all CMAQ funds but reduced a pound of emissions for $7.66. Transit service improvements and new services (not including alternative fuels) as a group, were somewhere in the middle, receiving 28 percent of funding and reduced a pound of emissions for $29.80. [N]

State DOT CMAQ Measures and Strategies

State DOTs undertake a variety of CMAQ strategies, including the following measures and examples: [N]

  • Washington State DOT provides assistance to urban areas subject to Commute Trip Reduction regulations requiring employer's to reduce trips and VMT to their worksites.
  • New York and New Jersey have statewide TDM policies that provide an overall framework for the role of alternative modes in state programs.
  • The state of Florida has a TDM policy within its statewide long-range plan. This also provides a framework for the technical and financial assistance Florida DOT provides to regional and local Commuter Assistance Programs. Florida DOT also supports research into alternative mode effectiveness and program evaluation.
  • Georgia DOT funds an independent evaluation of all alternative mode strategies in the Atlanta area to account for CMAQ funds spent and assess emission reductions toward the region's attainment strategy.
  • Several states maintain specific offices or staff positions for TDM coordination.
  • States in the Northeast tend to promote the use of their established transit networks as the primary alternative mode, while western states tend to support carpooling and vanpooling. Several states also have statewide telework initiatives.

Strategies to Enhance the Role of State DOTs in Supporting Cost-Effective Alternative Mode Strategies

Some state DOTs are supporting cost-effective alternative mode strategies in ways that go beyond the pass-through of federal funds. Many of these strategies are focused on improving the coordination between various stakeholders, including state air quality agencies, regional planning organizations, and local service providers. Per Arizona DOT's report on the topic, such support may include technical assistance, research, funding, and integration: [N]

  • State DOTs can provide technical assistance and objective guidance on how to project in advance and evaluate after implementation, the travel impacts of alternative mode strategies, since VMT reduction is at the heart of emission analysis. This can be made easier for other agencies through the development of software and on-line reporting that allows users to input simple data enabling the calculation of travel and emission impacts. State DOTs can take a leadership position in: 1) setting state-wide policy of the role of alternative modes in addressing air quality and other policy issues, 2) forming ideas on alternative mode projects, 3) providing insights in realistic emission reduction potential, 4) provide insights on funding restrictions applicable to these types of strategies, 5) communicating and coordinating with state air quality or health agencies, and 6) obtaining information from other states and national sources of information on alternative modes. To accomplish such assistance, ADOT is considering assigning a person from its headquarters staff (help-desk) and district offices to maintain the information and knowledge in this area and be the liaison to regional agencies and other state and federal agencies, or possibly utilizing several staff to provide guidance, answer questions, and perhaps maintain a page on ADOT's website.
  • State DOTs can foster and undertake research into the cost effectiveness of alternative mode strategies implemented within their state and help develop better methods and procedures for quantifying the impacts during project planning, funding, and reporting. Washington state and Florida DOT each have ongoing, dedicated research programs to evaluate alternative mode programs and provide guidance to district offices, regional agencies, localities, service providers, and others. Each maintains a TDM resource center for this purpose. Washington state biennially reports on the progress of its Commute Trip Reduction mandate to the state legislature, including what are the most effective strategies and how much it is costing employers to comply. The University of South Florida maintains the National TDM and Telework Clearinghouse for FDOT and FTA.
  • While most alternative mode strategies are planned and implemented at the regional and local levels, state DOTs can also fund or facilitate several support activities to bolster efforts within the state. For example, some state DOTs ( Connecticut, Michigan, New Mexico) coordinate fleet purchases of vanpools to lower the cost to the end user. Some underwrite vanpool insurance or purchase ridematching software and maintenance agreements. Other states fund alternative mode pilot projects ( Massachusetts, Oregon, and New York) to test new and innovative concepts that do not get funded under CMAQ, but are worth exploring. Finally, some states fund statewide activities to provide services not being undertaken at the local level. Some state DOTs have performed ride-matching and information services in parts of the state not covered by existing programs. Others have funded statewide initiatives (rideshare week, bike-to-work week) or air quality public education campaigns (like Clean Across Texas, ).
  • Finally, state DOTs control the management and operation of transportation facilities that affect how and when people travel and use their cars. Three notable facilities are HOV lanes, park-and-ride lots, and bicycle facilities on state roads. These facilities increase the convenience of ridesharing and using transit (park-and-ride), increase safety (bicycle lanes), and can provide travel time savings (HOV lanes) to alternative mode users. FHWA is redefining TDM as less of a planning function, and more of a set of strategies to be integrated into the management and operations of transportation facilities to improve the overall efficiency and effectiveness of the system. One major study of the HOV system in Los Angeles County pointed to the effectiveness of the HOV system, but the ongoing need to better coordinate HOV operations with ridesharing services and traveler information. [N]
  • Alternative modes are often a key part of the mitigation strategy for a major reconstruction project. However, states often perform this integration late in the planning process, not providing sufficient time or funding to realize the potential impacts of shifting travelers to alternative modes, routes, or time of day. Some states, including California, have built transportation management planning functions into the overall planning process for reconstruction projects. State DOTs can develop clear guidelines for identifying candidate alternative modes and integrating alternative modes into this process.
  • State DOTs can develop statewide policies regarding alternative modes and their role in addressing air quality objectives as well as other issues such as congestion, growth management, asset management, etc. This also provides the DOT a better foundation for commenting on CMAQ project selection decisions.


3.11.8 Tree Shading for Emissions Reduction
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While cars sit in the sun, gasoline evaporates from fuel tanks and worn hoses. These evaporated materials are principle components of smog. In 1999, the U.S. Forest Service and the University of California at Davis completed a pilot study to measure the difference in parking lot microclimate and parked vehicle emissions resulting from the presence or absence of shade tree cover. Results indicated that shade tree cover in parking lots reduced motor-vehicle hydrocarbon and nitrogen oxide emissions from cars parked in those lots. In this study, conducted in Sacramento California, interior vehicle temperatures averaged 45ºF cooler in the tree-shaded vehicle when compared with temperatures inside unshaded vehicles. Furthermore, increasing parking lot canopy cover from 8 percent to 50 percent would reduce total vehicle-generated hydrocarbon emissions by two percent and nitrogen oxide emissions by just under 1 percent in similar climates. In addition, this study noted that there was a user preference for shaded parking spaces.

Shade also extends the life of asphalt pavement. Trees in parking areas provide shade, visually reduce the impact of large pavement areas, and reduce heat gain. [N]

  • Use perimeter trees and shrubs to screen the parking area from nearby residential uses, while allowing for visibility by security ; personnel.
  • Design for a minimum of 50 percent canopy cover over parking areas.
  • Select tree species that do not drip pitch or attract aphids.
  • Where trees are planted near a bus route, or bus parking, limb trees to eight (8) feet above the ground.
  • Use planting areas to divide paved surfaces into smaller, more defined parking areas.
  • Consider end islands to delineate aisles and intersections and to protect the end vehicles. End islands should have raised curbs.
  • An alternative to planting in linear parking islands is the design of large concentrated planting islands within parking lots. This can allow plant communities to establish in these islands. They can also be stormwater infiltration areas.
  • Keep landscaping as low-maintenance as reasonably possible.
  • In high snow load areas, end islands may cause difficulties with snow removal. In these areas, large central planting islands may be& more appropriate. Consider snow storage needs and adjacent vegetation in high snow load areas.
  • In arid climates, irrigation may be necessary for plant survival.
  • These areas benefit most from tree shading of parking stalls in the summer due to higher temperatures.
  • Consider the use of structural soils under paved surfaces to allow root penetration without damage to the pavement and to retain parking spaces while increasing soil volume for trees in parking islands. This will benefit both the tree and long-term maintenance of the parking lot. Additional information can be found at the Department of Horticulture at Cornell University.
  • Interior planting islands should have drainage provided and depth to allow tree root growth at least 3 feet deeper than paving grade.
  • Plant trees to align with the painted parking stall lines to prevent their damage by car bumpers.
  • Car bumpers overhang tire stops and curbs. Consideration should be made in the design of sidewalks and planting areas for this overhang.


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Continue to Section 3.12 »
Table of Contents
Chapter 3
Designing for Environmental Stewardship in Construction & Maintenance
3.1 Beyond Mitigation: Projects to Achieve Environmental Goals
3.2 Context Sensitive Design/Solutions
3.3 Avoiding Impacts to Historic Sites
3.4 Designing to Accommodate Wildlife, Habitat Connectivity, and Safe Crossings
3.5 Culverts and Fish Passage
3.6 Stream Restoration and Bioengineering
3.7 Design Guidance for Stormwater and Erosion & Sedimentation Control
3.8 Drainage Ditches, Berms, Dikes, and Swales
3.9 Design for Sustainable, Low Maintenance Roadsides
3.10 Designing to Reduce Snow, Ice, and Chemical Accumulation
3.11 Designing to Minimize Air Quality Problems
3.12 Design and Specification for Recycling
3.13 Designing to Minimize Noise
3.14 Lighting Control/Minimization
3.15 Design for Sustainability and Energy Conservation
3.16 Safety Rest Areas, Traveler Services, and Parking Area Design
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