Traffic Calming 101

In an earlier blog, we discussed some possible ways that Vision Zero may affect DC streets. Traffic calming is one of the tools for making streets safer for our most vulnerable users, like pedestrians, bicyclists, children, the elderly, and the mobility-impaired.

Our roads are designed by traffic engineers. They tend to use the same standards that they use to design highways, even though neighborhood roads are used by a variety of users. When roads are “overbuilt” (ie: have more lanes than necessary, or wider lanes) they send signals to drivers that it’s okay to drive much faster than the posted speed limit. This is a design problem that can be addressed by the traffic calming measures discussed below.

According to a report by the AAA Foundation for Traffic Safety, reducing vehicle speeds, also called “traffic calming,” makes a big difference in serious injuries and traffic fatalities. When a person is struck by a car traveling at 15 mph, the risk of death is less than 5%. At 25 mph, the risk of death more than doubles to 12%. And if a person is struck by a car traveling at 45mp, the risk of death is 60%! Slowing down traffic can greatly reduce the likelihood of death or serious injury for vulnerable road users.

According to the Institute of Transportation Engineers, traffic calming is the combination of mainly physical measures that reduce the negative effects of motor vehicle use, alter driver behavior and improve conditions for non-motorized street users.

Traffic calming is the deliberate slowing down of traffic through neighborhoods by building speed bumps or other obstructions. Traffic calming helps to reduce crashes and increases the safety and convenience of pedestrians and other non-motorized vehicles. Neighborhood Streets Network noted traffic calming measures can also give children more space to play, decrease noise pollution and improve the scenery.  

This week, I’ll discuss some traffic calming measures suggested by the Project for Public Spaces you have probably seen in and around DC.

Road Diet

road diet

In road diet, planners and engineers reduce the number of lanes, or width of existing lanes, on the street. This is usually done by creating a separate space for pedestrians and bicyclists to travel. Road diets help reduce crashes by separating bicyclists from cars with physical barriers, making everyone’s commute better.

To learn more, check out this 2 minute video, which shows how planners can redesign a roadway.

Protected Bike Lanes

15th St. protected bike lane extension

Protected bike lanes visually reduce the width of the roads which can reduce drivers’ speed and separate bicyclists from cars by using curbs, planters, or posts.  Protected bike lanes increase safety for bicyclists and encourage new riders to travel for shorter trips, which reduces traffic on the roadways.  

Curb Extensions

A curb extension in Montreal.

A curb extension in Montreal. Photo by Gerald Fittipaldi on Flickr.

Curb extensions physically and visually narrow the roadway without reducing the roadway capacity.  Curb extensions force drivers to be more attentive and drive closer to the speed limit since they lower the design speed of a road. Curb extensions increase pedestrian visibility while decreasing the amount of time it takes to cross the roadway.

Roundabouts

roundabouts-1

Roundabouts are large, raised, circular islands at major intersections. Because the road narrows as a cars approach a roundabout, drivers tend to slow down. Roundabouts help to calm traffic by creating a steady flow of traffic. Since all drivers are traveling in the same direction and at a slower speed, crashes are less severe. Roundabouts are also safer for pedestrians and bicyclists because they only have to cross traffic coming in one direction and the distance is shorter than a typical intersection.

These are just a few of the traffic calming measures that can be used in a city. They each help slow down drivers, which can reduce traffic fatalities and serious injuries.

If you would like to learn more about how you can get involved in reducing traffic fatalities and serious injuries, join us for our community workshop:

Sunday, November 20th
1pm- 4pm
Dorothy Height Library
3935 Benning Rd. NE Washington,  D.C.  20019  

 

Alexandria Board Recommends Delay of Plan to Calm Traffic on King Street

King Street is the missing gap in the bicycle network. The City’s traffic calming plan will improve conditions for pedestrian and transit riders. Source: City of Alexandria.

Dan Mehaffey and Jim Durham are City of Alexandria residents and local advocates for safer streets for bicyclists and pedestrians.

Richard Baier, Alexandria Transportation and Environmental Services Director, presented on Monday a plan to meet the direction of City Council and calm traffic on King Street. The plan is the outcome of professional work by City Staff, numerous community meetings, and a compromise to keep as much parking as possible on King Street. The meeting went into the early hours of Tuesday when the Traffic and Parking Board voted 5-2 to recommend delay in implementing the plan, a change from a similar November 25th vote of 6-0 recommending delay. Board members Greg Cota and Kevin Posey voted against further delay after listening to Mr. Baier’s presentation and public comments, in which a majority of speakers, all Alexandria residents, spoke in favor of the City’s plan.                                                                                            

The flashpoint in the plan is the 27 parking spaces on King Street between West Cedar and Highland, where the majority of houses face North Terrace View, not King Street. Chairman Thomas “Jay” Johnson, Jr. heard testimony about the parking usage by City Staff. In 20 random samplings of the 27 spaces, the average count was 1.2 cars. At most, five cars were parked in the 27 spaces.  The 27 spaces do not include the 10 spaces west of Highland which were kept as parking spaces as part of a compromise that also added three additional spaces to the street parking on the other side of King Street.

Mr. Baier’s expert testimony focused on how the traffic calming measure before the board would re-allocate the use of public right-of way to create a safer King Street in a section that is heavily used by pedestrians to access the King Street transit hub. The Alexandria Transportation Commission, the Environmental Policy Commission, the Alexandria Bicycle and Pedestrian Advisory Committee, and the Park and Recreation Commission submitted letters of support for the plan.

The board also heard from Alexandria residents including residents of the affected neighborhood who favor the city’s plan and want the safety measures afforded by the city plan. The safety measures include pedestrian crossings, separation of use for walkers, bikers, and motorists, and a compliant lane narrowing shown by the Highway Capacity Manual to reduce speeds by between 1.9 and 6.6 miles per hour. The King Street speed limit is 25 miles per hour in the section, but motorist speeds are well in excess of the limit. Opponents of the plan also cited safety as a reason for their opposition to the plan described as safe by not only the professional planners on city staff but also in an independent review by a  professional engineering firm.

The traffic calming plan now goes to City Council for a March 15th hearing with the Traffic and Parking Board’s recommendation.

A clarification, from the Alexandria Bicycle and Pedestrian Advisory Committee: “Although the original parking information was technically correct, parking needs are based on peak usage not average usage. In an effort to be as clear as possible, we have updated the numbers to stress the peak usage for all parking in the stretch (six cars for 37 spaces) instead of the average usage for the 27 spaces that will be removed (just over 1 car).

Alexandria Board Recommends Delay of Plan to Calm Traffic on King Street

King Street is the missing gap in the bicycle network. The City’s traffic calming plan will improve conditions for pedestrian and transit riders. Source: City of Alexandria.

Dan Mehaffey and Jim Durham are City of Alexandria residents and local advocates for safer streets for bicyclists and pedestrians.

Richard Baier, Alexandria Transportation and Environmental Services Director, presented on Monday a plan to meet the direction of City Council and calm traffic on King Street. The plan is the outcome of professional work by City Staff, numerous community meetings, and a compromise to keep as much parking as possible on King Street. The meeting went into the early hours of Tuesday when the Traffic and Parking Board voted 5-2 to recommend delay in implementing the plan, a change from a similar November 25th vote of 6-0 recommending delay. Board members Greg Cota and Kevin Posey voted against further delay after listening to Mr. Baier’s presentation and public comments, in which a majority of speakers, all Alexandria residents, spoke in favor of the City’s plan.                                                                                            

The flashpoint in the plan is the 27 parking spaces on King Street between West Cedar and Highland, where the majority of houses face North Terrace View, not King Street. Chairman Thomas “Jay” Johnson, Jr. heard testimony about the parking usage by City Staff. In 20 random samplings of the 27 spaces, the average count was 1.2 cars. At most, five cars were parked in the 27 spaces.  The 27 spaces do not include the 10 spaces west of Highland which were kept as parking spaces as part of a compromise that also added three additional spaces to the street parking on the other side of King Street.

Mr. Baier’s expert testimony focused on how the traffic calming measure before the board would re-allocate the use of public right-of way to create a safer King Street in a section that is heavily used by pedestrians to access the King Street transit hub. The Alexandria Transportation Commission, the Environmental Policy Commission, the Alexandria Bicycle and Pedestrian Advisory Committee, and the Park and Recreation Commission submitted letters of support for the plan.

The board also heard from Alexandria residents including residents of the affected neighborhood who favor the city’s plan and want the safety measures afforded by the city plan. The safety measures include pedestrian crossings, separation of use for walkers, bikers, and motorists, and a compliant lane narrowing shown by the Highway Capacity Manual to reduce speeds by between 1.9 and 6.6 miles per hour. The King Street speed limit is 25 miles per hour in the section, but motorist speeds are well in excess of the limit. Opponents of the plan also cited safety as a reason for their opposition to the plan described as safe by not only the professional planners on city staff but also in an independent review by a  professional engineering firm.

The traffic calming plan now goes to City Council for a March 15th hearing with the Traffic and Parking Board’s recommendation.

A clarification, from the Alexandria Bicycle and Pedestrian Advisory Committee: “Although the original parking information was technically correct, parking needs are based on peak usage not average usage. In an effort to be as clear as possible, we have updated the numbers to stress the peak usage for all parking in the stretch (six cars for 37 spaces) instead of the average usage for the 27 spaces that will be removed (just over 1 car).”