Transportation Demand Management (TDM) is a term that encompasses a broad set of strategies intended to reduce or diffuse travel demand among modes, time, or routes within a regional or local transportation system. By providing choices and incentives for travelers to diversify their travel mode or behavior, TDM strategies relieve disproportionate pressures on segments of a transportation system.
Land use patterns can serve as either a source of or a solution to transportation demand. Land use is often incorporated into TDM strategies through the consideration of infrastructure planning, management, and development. TDM strategies that influence land use decisions - such as development incentives, zoning regulations, and alternative transportation programs ranging from carpooling to transit access - are most effective when used in concert with other TDM strategies.
Parking management strategies focus on the utilization of existing parking infrastructure instead of its construction. While many areas or businesses may advertise the availability of parking as an asset, the hidden external costs associated with low-cost, abundant parking are well documented. Land dedicated to paved parking increases stormwater runoff; raises construction costs that contribute to higher housing prices; and creates larger distances between destinations. Excessive or free parking generally decreases the incentive to walk, bike, or take transit by making automobile trips more convenient. By maximizing the use existing parking infrastructure before building more, the demand for vehicle trips in an area can be managed to promote livability.
Acton Parking Reserve Spaces -Town of Acton, MA
Developers in the town of Acton, Massachusetts may apply for a site plan special permit that allows land to be set aside but not immediately developed for parking. As stated in Section 10.4.4 (page 152) of the town's zoning code, a reduction of up to 75% of otherwise required parking may be allowed depending on the associated land use. Acton's parking reserve spaces allow time to demonstrate the true amount of parking needed, thus preventing the paving or construction of superfluous parking, which can induce traffic demand and hinder livable development patterns.
Landscaping and low-intensity development (such as playing fields) are often allowed on parking reserves. In some areas, parking reserves may also be allowed in return for other TDM strategies, such as employer-sponsored shuttles and van pools. The benefits of parking reserves include decreased construction costs, more flexibility for future land uses, and reduced environmental impacts. In addition, preserving the increased open space provided by parking reserves may compel neighboring land owners to find ways to keep driving demand from increasing in their area.
Glendale Flexible Parking Requirements for New Development - Glendale, CA
In 2007 the City of Glendale, California, completed a downtown mobility study as part of its Downtown Specific Plan. The city's goal was to accommodate new mixed-use growth while averting increased congestion. With no plans for major transit investment to accommodate new residents and visitors, the city used its mobility study as a way to create a mixed-use, livable downtown without needing to make expensive capital investments in transit.
The mobility study found that only 53 percent of available parking spaces in city garages were utilized, yet the free downtown parking area was regularly at 90 percent capacity. In response, parking rates were applied downtown while wayfinding signage directed drivers to free parking garages for longer-term parking. In addition, the city adopted new ordinances that allow TDM strategies to fulfill part of the minimum parking requirements for development sites. TDM strategies could include providing bicycle amenities, subsidized transit passes, preferred carpool parking, or sharing parking infrastructure with nearby developments instead. In addition to the more flexible parking ordinances, new residential and commercial developments of certain sizes are required to participate in a downtown Transportation Management Association to support alternative transportation programs and options.
Redwood City Market-Rate Curb Pricing - Redwood City, CA
Redwood City, California, created a parking system for its downtown business area that prices parking based on its proximity to surrounding land uses. More "convenient" spots near restaurants and businesses in the central business district are priced higher than parking spots further away. Prices fluctuate throughout the day to respond to rising and falling demand based on the nearby destinations - for example, parking near restaurants will be higher in the evenings and on weekends than during weekday mornings. The higher cost also prompts long-term users (such as employees) to seek lower-priced spaces farther away, leaving more spaces available for shorter-term business patrons.
Pricing zone map of parking in downtown Redwood City, CA | City of Redwood City
The market-based pricing scheme is designed to maintain an 85% occupancy rate of parking spaces, which balances revenue with maintaining consistent parking availability. In addition, the rate hedges against the need to increase parking rates, which can become politically sensitive. All revenue generated is used for improvements to the downtown area.
San Diego Shared Parking Agreements - San Diego, California
Shared parking may take two forms. One refers to large, often public, garages in an area that serve as the central parking areas for multiple surrounding uses. The other takes advantage of the differing peak times of adjacent land uses, such as a restaurant and an office building, in order to utilize the same parking infrastructure. In both cases shared parking uses land more efficiently and discourages multiple, single-use parking lots with multiple curb cuts along a roadway, allowing traffic to flow more smoothly. Removing rigid parking requirements also increases the variety of developments that can be built in closer proximity, creating a more vibrant environment that encourages walking and bicycling.
San Diego adopted an informal shared parking agreements in 2000 that encourages neighboring land uses within 600 feet and different peak activity times to utilize the same parking infrastructure. Shared parking is allowed in all zones of the city, except areas with single-family housing. In order to assist developers in understanding the legal process involved and encourage cooperation, the City created a shared parking template. As a part of its 2009 comprehensive downtown parking plan, the City also is exploring the development of a shared parking database that identifies lots and their peak demand times to encourage more shared parking arrangements.
Ridesharing and carpooling reduces single-occupancy trips by utilizing empty seats in traveling vehicles. Land use patterns influence the physical opportunities available for users to access carpools and transfer to other destinations or modes in the transportation network. Ridesharing can be a key strategy to expand the reach of a region's transit system to lower density area by providing a cost-effective link to areas without regular service. Formal and informal programs as well as technological applications help people connect and communicate about sharing rides.
Metro Transit Van Share and Pooling Programs - King County, WA
Commuter take part in King County Metro Transit van pooling | Commute Seattle
In operation since the late 1970s, King County (Washington) Metro Transit's commuter van program is the largest publicly run program in the nation. For a monthly fare that includes vehicle use, maintenance, and insurance, Metro Transit provides vans to groups of commuters that form to either commute to/from their areas of employment (van pooling), or to/from public transit system transfer points within a 10-mile radius (van sharing). In areas where land use patterns do not support regular transit service, a ridesharing service helps commuters access core job centers. Regional congestion is reduced by effectively expanding the reach of the transit system. Van pools and van shares also reduce the amount of land that must be dedicated to parking at employment centers and park-and-ride transit lots.
Metro Transit currently operates approximately 1,150 vans throughout the Puget Sound region, and estimates that the programs kept approximately 5,600 single-occupancy vehicles off the road in 2011. Potential participants can search for commuters with similar origins, destinations, and schedules through the www.RideshareOnline.com website, which is supported by Metro Transit and other transit agencies in the Pacific Northwest. Users that register for the site can also sign up to find carpool companions for special events or other activities.
San Bruno Proposed Mobility Hub - San Bruno, California
In areas with wide commute sheds and dispersed job centers, finding a rideshare or carpool opportunity with the same origin and destination can be challenging, especially if schedules must also be consistently synchronized among travelers. To add more flexibility to traditional fixed-route carpooling, a proposed transit hub between San Francisco and the Silicon Valley would provide a fixed physical location for travelers to connect and more easily customize their route. The concept mirrors other proposals being pursued in Seattle, Washington, and Tysons Corner, Virginia, among other places.
According to a concept paper presented at the Transportation Research Board's 2010 annual meeting by research firm Cities 21, a transfer point located along U.S. 101 outside of San Francisco would allow commuters traveling in carpools from their respective neighborhoods to find and transfer to car or van pools traveling to their individual destinations (such as an employer campus). The mobility hub could potentially link to transit and commuter rail stations, and serve as a dedicated area for employer-provided shuttles as well.
The mobility hub concept is designed to reduce the time necessary to find and organize appropriate ridesharing/carpooling opportunities, and to increase the variety of trips available to travelers. By serving as an easily recognizable and accessible meeting point, the hub also supports the nascent rise of "dynamic ride sharing," which utilizes smart phone and GPS technology to match potential ride- or car-sharers on an as-needed, flexible basis.
Location efficient development policies and incentives refer to programs or initiatives that both promote easy access to desired destinations (schools, stores, job centers, etc.) and affordability. Transportation demand is reduced when residential and commercial uses are planned to be within close proximity to each other, meeting a greater number of a community's everyday needs without requiring a car. Affordability is in turn supported by the reduced transportation costs associated with the location. The resulting density also helps support the implementation of other TDM strategies, such as ridesharing, increased transit service, and shared parking opportunities.
Affordable rental homes financed in
part with CATNHP funds.
| Cambridge CDD
Massachusetts Department of Housing and Economic Development
Locating affordable housing near transit service helps reduce transportation costs of households and reduces the demand for driving within an area. The Commercial Area Transit Node Housing Program (CATNHP) is intended to promote affordable housing development in areas served by both transit and community and commercial services statewide. The program is one of several statewide smart growth programs that incentivize municipalities to adopt compact development practices that reduce automobile dependency by providing greater transportation options. Originally passed in 2002, the program's success led to reauthorization in 2008.
CATNHP provides low interest financing for affordable housing developments of 25 units or less in designated commercial nodes, or of 25 units or more within Â¼ mile of a public transit node (including bus, subway, ferry, or commuter rail). The projects can be homeownership or rental construction, but half the units must accommodate residents with incomes no higher than 80% of the area median income.
Contact: Rachel Carlson, Massachusetts Department of Housing and Economic Development
Illinois Department of Commerce and Economic Opportunity
The Illinois State legislature passed the Business Location Efficiency Incentive Act in 2005. Businesses eligible for corporate tax credits under the State's Economic Development for a Growing Economy Tax Credit Program may receive additional tax credits if they locate their business near eligible affordable housing options or within a mile of regular transit service with pedestrian access from the job site. A housing or transportation remediation plan may also be submitted to receive the tax credits if the business moves to an area that is not considered location efficient. The Act lapsed in 2011 but was recently submitted to the legislature for renewal.
Contact: John Casey, Illinois Department of Commerce, Office of Business Development
Washington, D.C. Metropolitan Region
Fannie Mae's Smart Commute mortgage product program promotes a type of location efficient mortgage in select markets throughout the country, including the Washington D.C. metropolitan area. Location efficient mortgages are home financing instruments that factor in a home buyer's potential transportation costs into the mortgage-to-income ratio. Location efficient mortgages were originally offered to four pilot metropolitan areas (Seattle, Los Angeles, Chicago, and San Francisco) in 2003 through a collaboration between the Natural Resources Defense Council, the Surface Transportation Policy Project, Fannie Mae, and local lenders. Home buyers that select houses or condominiums in areas served by public transportation or employment centers (determined through a location efficient value formula) are eligible for higher mortgage amounts than they would be otherwise, since lower transportations costs leave more disposable income. For example, lenders may offer mortgages of up to 39% of a home buyer's income rather than the typical 28%.
Due to the complexity of the LEM application process and formula, Fannie Mae began promoting Smart Commute mortgages in partnership with State and local agencies and lenders throughout the country. Smart Commute mortgages require home buyers to simply live within designated distances from a public transit station and may include restrictions on car ownership. The Washington Regional Smart Commute Initiative includes discounts on transit passes and free membership to car sharing for program participants through numerous partnerships with area agencies and businesses.