A different way to slow speeders and protect workers in construction zones
This new approach to traffic monitoring and enforcement is more effective in slowing traffic over a longer distance
Sponsored by Jenoptik
By Laura Neitzel, Police1 BrandFocus Staff
Texas boasts the fastest speed limit in the nation ─ 85 mph on State Highway 130, a section of toll road between Austin and Seguin en route to San Antonio. Through much of the state, a speed limit of 80 or 70 mph is common.
It’s easy to drive long stretches of highway at a high rate of speed, lulled into complacency behind the wheel by light traffic and unremarkable scenery, when, suddenly, taillights brighten ahead of you. Cars, trucks and semis that had been stretched out a safe distance apart start bunching up, merging into a single lane.
Often, inattentive drivers will also barrel up behind you, passing on the shoulder and slamming on their brakes when they realize they just sped into one of the 3,100 active work zones on Texas highways.
According to the Texas Department of Transportation, more than 26,000 traffic crashes occurred in work zones in Texas in 2021, resulting in 244 deaths, a 33% increase in traffic fatalities over the previous year. Another 856 people were seriously injured. Fatalities included 195 motorists and vehicle passengers, 38 pedestrians, four bicyclists and three roadside construction workers.
Unsurprisingly, speeding and driver inattention were among the leading causes of work zone crashes.
This is not just a Texas problem. Across the 50 states, Washington, D.C. and Puerto Rico, there were more than 102,000 estimated total work zone crashes in 2020, according to the National Workzone Safety Information Clearinghouse.
While inattentive and aggressive drivers are unfortunately always going to be part of the highway landscape, there are strategies and devices that can help make drivers pay closer attention and slow their speed.
Construction zones pose hidden hazards
The traditional spot speed measurement, while effective in slowing traffic temporarily, can be less effective over a distance. What driver hasn’t seen traffic slow down when law enforcement is parked on the side of the highway, only to see it speed up again as soon as the trooper is out of sight?
Even more than normal roads, highway construction zones pose dangers that command attention. Uneven road surfaces, lack of stripes, narrow lanes and shoulders, detours, temporary on and off ramps, concrete barriers, road debris, changes in traffic flow and direction, and the presence of construction equipment and workers can all contribute to a hazardous environment. Work zones can often span for miles, and for both worker and driver safety, drivers need to maintain safe speeds for the entire distance.
One manner of keeping vehicles at a safe speed throughout a corridor is to create an enforcement zone with a series of point-to-point cameras, also known as average speed cameras.
Taking a different approach to speed control
Instead of measuring a vehicle’s speed at a specific point ─ like a single, fixed-speed camera does ─ fixed average speed cameras measure the average speed of a vehicle over a longer section of road.
In general, section speed control is based on recording a vehicle at both an entry and an exit point ─ like the beginning and end points of a highway construction zone ─ with each point equipped with cameras for automatic license plate recognition (ALPR). Each vehicle is recognized at each checkpoint, and the vehicle is matched by its license plate number using ALPR.
The system then calculates the average speed from the known distance between the zone entry and exit and the time taken for each vehicle to pass. These values can be compared with the time a vehicle should take driving at the speed limit allowed, taking into account speed limit changes throughout the zone.
This approach has proven effective at slowing traffic over a longer distance. If a driver has exceeded the speed limit to pass but then slowed back down, that will be calculated into the average speed over the measured section. In construction zones speed control is usually announced in advance with road signs and enforced with the doubling of traffic fines while workers are present. Measuring average versus spot speed helps law enforcement distinguish between motorists who temporarily exceed the speed limit to pass another vehicle and scofflaws speeding long distances undeterred throughout the construction zone.
Create a system, influence driver behavior, save lives
Over larger distances, multiple average speed cameras can be integrated into one system, as has been the case in other parts of the world.
In Australia – a country with a land mass 11 times bigger than Texas – regional departments of transportation have been using point-to-point camera systems in both urban and rural areas to reduce road speeds and improve road safety and traffic flow.
In Scotland, more than 350 kilometers (220 miles) of roads have been equipped with Jenoptik’s average speed camera systems. Before the installation of average speed cameras on a particular 80-kilometer (50-mile) stretch of the A90 freeway between the center and northeast of Scotland, only 40% of drivers adhered to the 70-mph speed limit. After installation, the speed limit is now adhered to by 99% of drivers.
From Scotland to Australia, this approach of creating systems of average speed cameras has been shown to positively influence driver behavior and compliance with speed limits, resulting in fewer accidents, improved traffic flow and even lower carbon emissions.
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