Radar Speed Signs Increasing Work Zone Safety

I RECENTLY HAD a chance to speak with Tad Blanton, a field operations supervisor for Medford, Oregon’s Public Works. He manages four crews that work year round on every type of public works project you can imagine – from underground maintenance to structural repairs, paving and concrete work. Many of the projects take place outdoors alongside moving traffic.

He told me that about three years ago, he got a call from someone in the city’s electrical repairs department. The guy had just seen a demonstration of a speedcheck radar speed sign from Information Display Company and thought Tad should check it out himself…and he did.

After the demo, Tad spoke with the folks at IDC and arranged to have one of their speedcheck displays loaned out for a few weeks. Tad said that providence brought the radar speed sign to his department when it did. They were just about to begin work on a storm drain repair project that would have them in the middle of heavy traffic – traffic that could not be shut down or detoured.

Tad told me that his crew came back entirely surprised and enthusiastic about the radar speed display. They told him that the difference the display made in slowing cars and increasing safety was (and I quote) “absolutely unbelievable.”

Of course, the city has since purchased several speedcheck radar speed signs from Information Display Company. When I spoke to Tad, he told me that even the original speed display – the one they first received as a loaner -  is still working as well as it did the first day they used it - and that was three years ago.

Fact is, the Federal Highway Administration reports that nearly 1,000 people are killed and more than 40,000 injured each year as a result of motor vehicle crashes in work zones. The majority of these cases involve excessive speeds.

Add to this the fact that an estimated 20 percent of our national highway system is currently under construction, and you have a lot of potentially hazardous work zones (about 3,000 on U.S. highways alone) Add to that thousands more including work being done on public streets, around construction sites and on public works projects, and were looking at thousands of work zones across the U.S. and thousands of workers and drivers at increased risk.

While we all look forward to getting America back to work and having some upgrades made to our nation’s infrastructure, let’s not forget about the safety element. Tad and the city of Medford would agree that radar speed signs could have a huge impact on keeping both workers and drivers safer in work zones.

I HEARD A disturbing statistic a while back that I can’t seem to get out of my mind. Information Display Company had loaned some radar speed signs to Feet First, a great organization all about getting kids (and their parents) to walk rather than drive to and from school. One of Feet First’s directors told me that half of school children hit by cars in school zones are actually hit by parents of students at the same school. I would think that of all the drivers on the road during school hours, these drivers would be most cognoscente of the potential hazards and therefore the most cautious. Apparently not.

Then I came across a new report just put out by Safe Kids USA that might explain this phenomenon. The report, entitled Distracted Drivers In School Zones: A National Report, highlights some statistics regarding driving behavior – particularly in school zones. What they found was that school zone drivers are often distracted and distractions have a real impact on safe driving. Consider some of these statistics highlighted in the report:

• It takes about .25 seconds for an average driver to identify a road hazard (such as a child running out into the street)
• It takes another .25 seconds for the brain to process the situation
• And another .25 seconds for the driver to determine his/her course of action

As the report lays out, if the driver is traveling 30 mph in a school zone, his car will go 33 feet before he even reacts to the hazard.  THEN…

The car will travel another 33 feet by the time the driver applies the brakes…

and another 38 feet before the car actually stops.

Total braking distance from the moment the child is spotted till the car stops…104 feet.

That is IF the road is dry and IF visibility is clear and IF the driver is totally attentive.

On the other hand, if he or she is distracted  – say, by a cell phone call, or a GPS device, or a talk show host, or grooming, or kids in the back seat, or…Well, let’s just say, stopping distance can be greatly larger.

The Harvard Center of Risk Analysis estimates that, in 2003, cell phone use by drivers was a factor in 636,000 crashes involving 12,000 major injuries and 2,600 deaths. Now, add to this other distractions like eating or reaching for that CD cover under the seat.

One more quick bit of information. In 1999, the U.S. Department of Transportation issued a report that highlighted the impact that the speed of a car has on the severity of injuries once an accident does occur. According to the report, only 5 percent of pedestrians would die if hit by a car traveling 20 mph or less. This fatality rate jumps 8X – to 40 percent – when the car is traveling just 10 mph faster, and 80 percent when traveling 40 mph.

So if there was a way to slow drivers just a bit – say from 30 to 20 mph – while driving through a school zone AND a way to draw driver attention from distractions back to their own driving speed, we can make a real impact on the number of accidents and the severity of injuries that occur in school zones.

And that, in a nutshell, is the reason why studies show radar speed signs to be so effective at increasing pedestrian safety in school zones. Long after speed limit signs and school zone posting have become all but invisible to passing drivers, radar speed signs continue to grab driver attention and refocus attention away from distractions and back on their own driving speed.

I really like Feet First’s idea of getting our children back in the habit of walking and riding their bikes to school. I like it even better when I know we are doing all we can to increase pedestrian safety around school zones. The evidence clearly points us in the required direction – eliminating driver distractions and reducing speeds.

30+ radar speed signs in Bellevue, WA

Perhaps the most comprehensive field study on the effectiveness of radar speed signs was just conducted by the city of Bellevue, Washington. Results were so overwhelmingly positive that the city rewrote their own rulebook on when and how to use these traffic-calming displays.

Prior to the study, Bellevue city officials viewed radar speedcheck signs as a secondary fallback option for applications where speedbumps, traffic circles or other physical traffic calming measures just could not be installed. But that has changed. Due in most part to the results of their own study, Bellevue has now installed more than thirty permanently mounted radar speed displays around school zones, on neighborhood streets and other locations where speeding traffic is a concern – and in many cases, in locations where speedbumps might once have been employed.

Old habits are hard to break. It doesn’t take a scientist to conclude that a big obstruction in the street (speedbump) will tend to slow drivers, and so installing them has often been the knee-jerk response that many cities exhibit when speeding traffic becomes an issue. 

What simple observation may not show, however, are some of the signficiant drawbacks to speedbumps. Drivers, for instance, oftentimes increase their speed from bump to bump. Speedbumps slow fire trucks, ambulances and other emergency vehicles and may increase traffic noise and present a hazard to bicyclists and handicap pedestrians.  The installation of speedbumps often result in simply shifting traffic from a main through route to quiet neighborhood side streets.

According to the Bellevue report, radar speed signs have a similar effect in slowing traffic, without the drawbacks associated with traffic calming road obstructions. Speedcheck signs have no effect on emergency vehicles or bicycles. They don’t cause increased traffic noise and they don’t cause damage to your automobile.

Perhaps most surprising to those following the Bellevue study is that the radar speedcheck signs continued to be effective over a long period of time. In some cases average traffic speeds continued to decrease years after the radar displays were first installed.

The Bellevue report not only provided evidence of the effectivness of radar speedcheck signs but also provided experienced recommendations on choosing and installing the displays. A review of these findings coming up in our next blog post.

The facts are clear. Comprehensive traffic signal timing programs work. A list of just some of the proven benefits is impressive:

Timed traffic lights in Longview, WA

▪  Reduces delays
▪  Eliminates traffic congestion
▪  Reduces fuel consumption
▪  Relieves driver frustration
▪  Reduces speeding
▪  Increases pedestrian safety
▪  Improves air quality
▪  Saves cities money
▪ Reduces thru-traffic on
secondary streets

Studies after studies have quantified the benefits that traffic signal timing brings to a community.

A 1995 report from the Texas Department of Transportation concluded that a traffic light synchronization program in Texas saved drivers 20.8 million gallons of gas, 22 million hours of delay time and 729 million stops. The program covered 1,348 intersections in 43 cities and in 1995, cost $7.7 million dollars to implement. The total savings to drivers by way of fuel consumption and delays alone is estimated at $252 million in the first year. This comes out to a whopping $32.30 in savings for every dollar spent on the project!

The results obtained in Texas are no anomaly. Similar results were found by various cities across the U.S.

 ▪  In Los Angeles, a city that knows something about traffic congestion, their Adaptive Traffic Control System (ATCS) was shown to reduce travel time by 12.7 percent, cut stops by more than a third and decrease delays by 21.4 percent.

▪  California’s Fuel Efficient Traffic Signal Management Program (FETSIM) resulted in an 8.6 percent reduction in fuel use, 15 percent fewer delays and an overall 7.2 percent savings in travel time.

▪  By synchronizing the lights along an 11 intersection throughway, the city of St. Augustine, Florida realized a 36 percent reduction in delays, an annual savings of 26,000 gallons of gas and a cost savings of $1.1 million.

▪  In Portland, Oregon, city officials spent $70,000 to time 35 traffic signals and saved over 175,000 gallons of gas per year. 

Texas Transportation Institute findngs

These examples represent the good news. The bad news is that according to the United States Department of Transportation, as much as 75 percent of the traffic signals across the U.S. are not optimized for smooth traffic flow. If improvements were made, the U.S. would save about 17 billion gallons of motor fuel each year and reduce harmful emissions by up to 22 percent. A driver that commutes 2 hours to work each day would get back 50 hours of his/her life each year.

Integrated traffic signal systems (ITS) may vary but typically include several components such as an automated data collection device, a centrally controlled traffic signal synchronization system, interconnected traffic signals and adaptive signal controls. A maintenance management program ensures that traffic light synchronization is coordinated along with traffic pattern changes such a commute direction or special events. As longer-term traffic patterns change, signal timing will have to be adjusted. According to DOT, operations and maintenance typically require one traffic engineer for every 75 to 100 signals and one signal technician for every 40 to 50 signals. Retiming should be performed every two to three years at a minimum.

It’s also important that drivers understand that lights are synchronized and that they know the rate of speed they must maintain in order to hit all green lights. To accomplish this, the city of Longview, Washington, installed TrafficFlow Manager displays along their timed routes. Integrated together with the timed traffic signal system, the electronic signs automatically adjust the posted speed limit to inform drivers of the optimal speed they need to travel.

Sounds expensive? Actually, costs for entire ITS systems range from around $3,000 – $5,000 per updated signal. And as we saw in early examples, once installed, cost savings ratios are enormous – 17:1 in California; 62:1 in Texas.

So where do you start?

If you’re looking to get your local officials on board, you may want to firsts send them to this blog or to some of the linked reports. If you’re a city traffic engineer or government official, you may want to start by contacting those that can provide more information on requirements, technologies and funding.

Below are some suggested links:

Research & Innovation Technology Administration: Intelligent Transportation Systems

ITS Application Overview

FHWA Office of Operations, Arterial Management Program

National Traffic Signal Report Card

The Consortium on ITS Training & Education