October 5, 2005
TRAFFIC SLOWING INITIATIVES
By: Kevin E. McCarthy, Principal Analyst
James J. Fazzalaro, Principal Analyst
You asked for a description of measures used in Connecticut to slow traffic, specifically traffic calming initiatives and enhanced speed enforcement programs, and information about their effectiveness.
Traffic calming consists of a wide range of measures designed to reduce traffic speed, discourage motorists from cutting through residential areas, and reduce the number of accidents. These measures can include physical changes to streets, such as erecting speed humps (segments where the street is raised several inches for a length of several feet), bump-outs (extensions of the sidewalk to narrow the traffic lanes, particularly at crosswalks), and chicanes (changes in the alignment of lanes). Other measures affect how drivers perceive the roadway, e.g., painting lines on the road to make lanes appear narrower and planting trees or shrubs along roads. Traffic calming can also involve education and speed limit enforcement. The Institute of Traffic Engineers has two websites, http://www.ite.org/traffic/index.html and http://www.ite.org/traffic/tcstate.htm#sartm, that provide additional information about traffic calming, including illustrations of various traffic calming measures.
Many towns in Connecticut have implemented traffic calming measures. Hartford and Stamford have particularly sophisticated programs, which extensively involve the residents of the areas that would be affected. Other towns that have implemented traffic calming measures include Mansfield, Norwalk, South Windsor, and West Hartford. Enfield has adopted an ordinance specifying the process by which traffic calming measures would be implemented, although no measures have been adopted to date.
Information on the effectiveness of traffic calming initiatives in Connecticut is mostly anecdotal. However, Hartford found that the measures reduced traffic speeds and substantially reduced the number of crashes in most cases. Norwalk is currently conducting a study on the effectiveness of speed humps, the city's primary traffic calming measure.
Towns routinely reassign police officers to enhance enforcement of speed limits in response to resident complaints. However, this is invariably a short-term response due to resource constraints, according to the Connecticut Chiefs of Police Association. Many towns also use portable or permanent radar units that display the posted speed limit and a motorist's actual speed as part of their speed enforcement efforts. In several towns, as described below, enhanced speed enforcement is used in conjunction with traffic calming initiatives. Anecdotal information suggests that these measures reduce speed, but that the effect decays relatively quickly.
A number of municipalities in other states use photo radar systems to enforce speed limits and red light laws. The information collected by these systems is currently not admissible in Connecticut courts, and therefore they are not used here. OLR report 2001-R-0403 provides additional information on the use of these systems in enforcing speed limits. OLR report 2004-R-0540 discusses their use in enforcing red light laws, as well due process issues raised by the use of these systems.
TRAFFIC CALMING INITIATIVES
The city conducted a traffic calming plan during the period 2002-2004 at a cost of $500,000. Among the measures considered were curb extensions, roundabouts, chicanes, a modified form of speed humps called speed tables, and raised intersections. The city also considered the use of “road diets,” i.e., narrowing travel lanes and eliminating unnecessary lanes to accommodate parking, turn lanes, and bike lanes.
The planning process involved collecting traffic volume and speed data from nearly 500 intersections, holding extensive meetings with neighborhood groups, and conducting focus groups and charettes (design workshops), The information provided by the community, along with previously collected data, allowed the planning team to develop a set of solutions to address each neighborhood's speeding and traffic concerns. The team determined the feasibility of installing a particular type of traffic calming measure at a location after considering issues such as: storm water drainage; subsurface utilities; handicap access; maneuverability of buses, snow plows and garbage trucks and other issues that could affect the implementation of the measure. The approach also sought to avoid shifting traffic problems from one residential street to another. The team developed a citywide master plan addressing these concerns.
Although there is no separate budget for implementing the plan, the city has installed measures as opportunities such as construction projects arose. For example, in September of 2003, Maple Avenue and North Main Street were scheduled for resurfacing and re-striping. Because new pavement markings were already in order, and the master plan called for these streets to undergo road diets, the city was able to implement these measures at little to no additional cost. Other streets that have undergone road diets include Capitol and Tower avenues. Other measures, such as the ones proposed on streets and intersections that were identified by the community as higher priorities, may be constructed as stand alone projects.
Perhaps the most visible measure has been the creation of chicanes on Whitney Street in the city's West End. The street was re-striped to create alternating, one side of the street parking areas. The travel lanes thus form elongated S-curves in order to encourage drivers to slow down. In addition, bicycle lanes have been added in each direction.
The city found that these measures reduced traffic speeds in 14 of the 19 cases studied after implementation, generally by two to five miles per hour. It found that the measures reduced crashes by 25% on Whitney Street, 60% on Capitol Avenue, 38% on Main Street, and 35% on Tower Avenue. On the other hand, the measures did not reduce crashes on Maple Avenue. An ITE conference paper, available on-line at http://ite.org/Conference/papers/CB05B1002.pdf, has an extended discussion of Hartford's program.
Mansfield initiated its traffic calming program in the mid 1990s. It has installed speed humps, textured pavements, diverters, and other measures, primarily to control speed on town roads. (Textured pavements use bricks or other distinctive paving materials, often at crosswalks or other areas where slower speeds are desired.) The town has considered installing roundabouts, but has not done so to date. It has also used a portable radar unit with a speed display in conjunction with these measures.
The city has made extensive use of speed humps to reduce traffic speed and address other traffic problems. The city began a pilot program in 2000 installing speed humps near two public housing complexes. Since then, the city has budgeted $100,000 per year for traffic calming measures, primarily speed humps. In FY 05, the city installed speed humps on 10 streets, with an average of four humps per street.
The city has a formal process by which residents can request a speed hump. Proponents are asked to circulate a petition to the homeowners on the affected street to find out whether there is support for the speed hump or considerations that the proponents had not recognized.
Residents who wish to have a speed hump installed on their street must submit a letter to the Department of Public Works (DPW) requesting a speed hump, together with a petition signed by area residents indicating support for the project. DPW then conducts a traffic study. To be eligible, the street generally must have a volume of 3,000 or fewer vehicles per day. If the city determines that the traffic volume is insufficient to warrant a city-funded speed hump, the residents can arrange for the city to erect one under its Freeholder's Procedure, under which the residents are assessed for the cost of the speed hump on their next property tax bill. In any case, the street must have no more than two travel lanes and cannot be a designated emergency route. It must be no more than 40 feet wide with a grade of less than 8% approaching the speed hump.
When a street is next in line for speed humps the DPW will send a letter to all property owners on the street. The letter will request that the property owner indicate “yes” or “no” to speed humps on the street. At least two-thirds of the residents must vote in favor for the project to go forward.
The town worked with the developer of the Evergreen Walk commercial center to incorporate several traffic calming measures. These include raised crosswalks, crosswalks that use paving materials with a different texture to encourage motorists to slow down, bumpouts, and roundabouts. Since this is a new development, the town does not have baseline data that could be used to determine the effectiveness of the measures. The town is also installing traffic calming measures on Kelly Road, a collector in a residential area. This $60,000 project will include mid-block crosswalks, pedestrian islands, and painting lane lines to narrow the perceived width of the roadway.
The city has operated a traffic calming program for over eight years and has spent approximately $1 million on traffic calming measures on local streets throughout the city.
Historically, the program has operated in response to requests by residents. City staff meet with residents, neighborhood associations, and local government officials to discuss traffic issues and identify the potential sites of traffic calming measures. The staff also sends questionnaires to residents of the affected area and collects data on existing traffic conditions. The staff meets with residents of the area to review the questionnaire results and the existing conditions report. The staff then establishes a residential steering committee and prepares a traffic calming plan.
The plan can contain one of two levels of measures. The first level includes such things as speed humps, bicycle lanes, and marking streets to narrow lanes. The first level also includes enhanced enforcement of speed limits and education of residents on traffic issues. The education component consists of using a portable radar trailer that informs the public of the speed limit and their actual speed. After the trailer operates for several days, the police use targeted patrols to enforce the speed limit.
The second level includes more intrusive measures, such as creating roundabouts, chicanes, and curb extensions; installing traffic signals; and restricting turns. The second level measures are only implemented if the first level measures have not resolved the problem.
The staff prepares a final report for the area, present their recommended measures to the city's traffic advisory committee, and obtain the approval of the legal traffic authority. The neighborhood association and local officials must also support the measures in order for them to be implemented. The staff present the approved recommendations at a public meeting. At least two-thirds of the residents of the area must endorse a petition for the recommended measures in order for them to be implemented.
The city uses the following criteria to rank projects for funding purposes: peak hour and 24-hour traffic volume; traffic speed; accident data; the proportion of traffic that is cutting through the area; and the location of schools, elderly housing complexes and senior centers in the area.
Additional information about Stamford's program is available at www.ci.stamford.ct.us/TransportationPlanning/calming.htm. The city is currently preparing its first city-wide traffic calming plan, rather than merely responding to resident requests.
The town has implemented a wide range of traffic calming initiatives, including:
1. installing raised and planted medians on Asylum and Farmington Avenues,
2. eliminating lanes and widening sidewalks on Farmington Avenue east of the town center, and
3. establishing bump-outs on the Boulevard to provide protected areas for parking.