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Traffic Calming: What Are the Most Effective Techniques?

Traffic Calming

There’s no doubt that slower vehicles make roads safer for pedestrians, bicyclists, and other motorists, but what’s the best way to persuade motorists to reduce speeds without creating traffic congestion?

Traffic calming techniques use physical devices to accomplish these goals.

In this article, we will take a closer look at various traffic calming techniques, their cost effectiveness, and some next-generation technologies that could offer further improvements.
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What is Traffic Calming?

Suppose that a resident complains about vehicles speeding on a residential street. Cursory research also shows that bicyclists have been hit while crossing the street. One solution might be to install a new stop sign or traffic signal to slow down traffic and enable bicyclists to cross the street safely.

The problem is that traffic signals have a high initial cost and significant ongoing maintenance costs. At the same time, both stop signs and traffic signals can increase traffic congestion and carbon emissions.

Traffic calming techniques can help address the problems without slowing down traffic.

Physical traffic calming devices can help slow down traffic without forcing drivers to an arbitrary complete stop. For example, speed humps, speed cushions, speed tables, and radar signs have all been shown to be effective at reducing vehicle speeds, but drivers aren’t required to wait or make a complete stop.

High Tech vs. Low Tech

Traffic calming devices can be generally divided into high-tech and low-tech categories. While the right solution depends on the specific situation, it’s worth exploring the cost and effectiveness of each option in order to make an informed decision. The options have significant differences in cost and effectiveness, but a few of them stand out from the rest.

Download our worksheet for identifying pedestrian and bicycle safety solutions.

Low-Tech Solutions

Low-tech traffic calming solutions involve redirecting traffic or introducing physical barriers to encourage drivers to slow down. These solutions often mean higher costs, detailed planning and road closures during construction. They may also need to be maintained over time, depending on the solution.

Here are some of the most common low tech solutions:

  • Deflecting vertically or horizontally by adding speed humps or chicanes can help slow traffic without forcing vehicles to stop. Speed humps cost approximately $2,500 each and slow traffic by an average of 18 to 19 percent, making them one of the most cost-effective low-tech options.
  • Narrowing traffic lanes by adding bike lanes or curb extensions can help slow traffic and improve pedestrian and bicyclist safety. Re-striping costs between $5,000 and $30,000 per mile and reduces speeds by less than five percent, while curb extensions can cost $10,000 to $40,000 and reduce speeds by around four to five percent.
  • Restricting access with median diverters or pedestrian zones can help reduce the amount of traffic, but could increase congestion on nearby streets. The cost of restricting access varies depending on the project, but it is a very effective way to reduce traffic speeds—although there could be a cost in terms of traffic congestion elsewhere.

High-Tech Solutions

High-tech traffic calming solutions involve placing signage on a road or implementing technology on the road itself to help make drivers more aware of their speed and slow them down. Since they typically aren’t built into the road, these solutions tend to be less costly and easier to implement than low-tech solutions.

Here are some of the most common high-tech solutions:

  • Radar signs provide motorists with immediate feedback about their speed to encourage them to slow down. Radar signs cost between $2,000 and $5,000 and reduce traffic speed by an average of about 20 percent, making them very cost effective. The signs can also be moved as-needed.
  • Flashing beacons provide a warning when motorists enter an area where they should slow down. Flashing beacons cost about $2,000 and reduce speeds by about five percent, making them another cost-effective option.
  • Smart midblock crosswalks provide ways for pedestrians and bicyclists to cross busy streets, while slowing traffic only when required. These crosswalks cost an average of $2,500 to implement and have very high rates of compliance.


Next Generation Tech

Suppose that speed humps are installed to slow traffic on a street near a school. While the traffic calming approach is effective, traffic will remain slow even when school isn’t in session, potentially causing unnecessary congestion. Next-generation solutions take a more intelligent approach.

Don’t forget to download our worksheet for identifying pedestrian and bicycle safety solutions.

Data-Driven Decisions

Smart city technologies enable planners to have a detailed, high-level view of their entire road network. By automatically recording traffic flow, traffic engineers can quickly determine streets where traffic calming is necessary before safety issues arise or citizens begin to complain.

Leveraging a data aggregation tool, such as Glance Performance Measures, allows you to create reports with detailed statistics and insights into where your traffic system has issues. Armed with this data, cities can plan out the best approach to mitigate traffic issues without relying on citizen complaints.

Smart City Solutions

Smart city technologies incorporate real-time traffic information to slow traffic when needed, but encourage maximum flow when not in use. A great example would be a School Zone Flashing Beacon, which can be remotely programmed to only operate when school is in session.

We offer a variety of smart city solutions:

  • School Zone Beacons – Our school zone flashing beacons can be remotely programmed to make changes to their schedules at any time. For example, if school has been canceled due to bad weather, the beacons can be turned off to maintain traffic flow.
  • Glance TravelSafety – Our TravelSafely app integrates with smart city infrastructure to alert motorists, bicyclists, and pedestrians when they enter unsafe conditions. This can help slow traffic only when necessary.
  • Connected Traffic Signals – Our connected traffic signals enable you to convert raw traffic data into actionable insights to help improve traffic flow and/or calm traffic as needed when pedestrian or bicycle traffic is elevated.

Getting Started

Applied Information offers a variety of smart city solutions designed to help mitigate congestion and calm traffic. These technologies work with existing infrastructure to provide smart city benefits without having to make massive change.

Join the Conversation

  • Travis says:

    I live on a residential street that also happens to be a potential route between two major roads. We get a lot of non-resident traffic going 35-40 mph. At the end of our street the road takes a hard 90 degree turn, which cars frequently cut, drifting well into the lane of oncoming traffic, literally squealing tires as they go around the corner. There’s an elementary school just a few blocks away, and there are plenty of kids out playing, people walking their dogs, jogging, and all the typical residential fare. I really don’t want a child’s death to be the cause of traffic calming. We need to be proactive about this and find a way to get people to slow down, or stay on the arterial roads.

    Speed bumps are effective, obviously, but they’re unsightly and make the experience of driving through our neighborhood significantly less enjoyable for all. I think something as simple as a concrete median with a flashing light going into and around the 90-degree corner might be enough to really slow people down.

    Does anyone have any other suggestions or recommendations about how to slow down traffic in a scenario like this?

  • ZZ T says:

    In the “old days” cops would set up radar traps. One cop behind a tree or mailbox with radar and several cop cars around the curve out of site waiting to pull cars over and ticket. Worked great as long as they kept coming back every month or so to reinforce the zone. Today, cops are likely too busy coping with addicted people, picking up the pieces of broken families, suppressing riots/mayhem, and begging for more funding to offer radar traps (but you can try).

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