Cutting work zone carnage

This is the National Work Zone Awareness Week in the US (7-11 April) and suppliers are finding new, cost effective ways to apply technology to improve safety in road construction zones.

The American Road & Transportation Builders Association (ARTBA) and members of its Traffic Safety Industry Division (TSID) are world leaders in developing and deploying cutting-edge technologies, such as cameras, sensors and other input devices, automated data processing, dynamic message signs, web sites, highway advisory radio as well as improvements to road markings.

Useful work zone technology does not always involve electronics. 3M recently introduced a new high-build resin for pavement markings to increase durability and provide an all-weather optics system that performs well in wet and dry conditions. The “All Weather Paint” provides bright pavement markings, even when a roadway is drenched with water.

Because of its high-build resin, the paint can be applied more thickly than conventional highway paint, thus increasing the life of the paint and reducing the frequency with which the road markings will need to be painted – thereby reducing workers’ exposure to traffic.

3M also recently introduced Diamond Grade reflective sheeting for road signs, which uses the latest prismatic technology to maximize the visibility of signs to drivers of all types of vehicles.

Automatic evaluation

The latest ITS technologies automatically evaluate road conditions and communicate immediately with motorists, saving time and lives. This is particularly important in work zones, where conditions can change abruptly. Roadside computers operate autonomously collecting and analyzing data, to make “decisions” regarding what messages to display, and automatically update portable changeable message signs (PCMS), radio messages and web sites to reflect the traffic conditions.

A good example of the value of such technology comes from a bridge replacement work zone in North Carolina where more than 50 incidents of hydroplaning were reported on the temporary lanes used to detour traffic. North Carolina DOT deployed an automated hydroplane detection/alert system developed by Quixote Transportation Safety. When the pavement was dry, the PCMS was blank; when the pavement was lightly wet the displayed message was “Wet Pavement Ahead; Observe Speed Limit”; when water depth reached 6 mm, the display automatically changed to read “Standing Water Ahead; Reduce Your Speed.”  After deployment, no accidents were reported due to wet pavement conditions.

Accidents in work zones often occur where lanes merge. International Road Dynamics has successfully deployed a lane merge system that provides both “early merge” and “late merge” instructions, to control traffic flow.

The “early merge” system uses a series of trailers with microwave radar sensors to monitor traffic flow. On cue, lights flash on signs that read “Left Lane Do Not Pass When Flashing.” When vehicle congestion develops, the dynamic work zone creates a “No Passing Zone” prior to the construction zone, instructing motorists to merge early to prevent backups that often occur when drivers wait until the last minute.

A study of the effectiveness of the dynamic early merge system in Michigan suggests it helped to reduce peak period travel time, cut aggressive driving behavior (late lane merges), smoothed traffic flow, and helped to cut the number of crashes.

Protection for workers on foot

Technologies for collision warning and protection of workers on foot are generating a lot of interest from contractors, government agencies and labor groups. Several technologies are being refined to alert drivers of everything from fork lifts and dump trucks, to cranes and excavators when workers-on-foot are present. Tag Safety Systems, for example, is perfecting processing hardware to detect workers and alert drivers and operators

In addition to collision warning devices, future vehicle electronic safety systems are likely to include tip-over monitors, computer control of machine movement under heavy loads, vehicle status monitors, fleet management network connections, logistics and supply chain information systems, and other features. Such worker protection technologies will be provided as standard ‘original equipment’, which is likely to have much greater customer acceptance than ‘after market’ installations, since sensing, computing, and display hardware can be shared, cutting costs.

Energy Absorption Systems’ new trailer-mounted attenuator (TMA) protects workers from passing traffic while minimizing potential damage to the host construction vehicle, to which TMAs are traditionally directly attached. The SST Safe-Stop Truck Mounted Attenuator requires minimal modification to host vehicles. Should a collision occur, the unit’s steel support frame collapses and the aluminum cartridges crush to absorb the energy of impact, bringing the impacting vehicle to a controlled halt. Anti-rotational dampeners lock the TMA in place during an angled impact to minimize the possibility that the impacting vehicle will enter a work zone or adjacent lane(s).

A recent study by the Texas Transportation Institute (TTI) found that “highly portable positive protection technologies” are a cost effective means to protect workers when other types of portable concrete barrier (PCB) cannot be cost-effectively deployed for short-term projects. Barrier Systems has introduced the ArmorGuard Barrier, which uses a reinforced steel design to create a portable freestanding barrier designed for short term, short duration work zone applications. It consists of 8.5m (28-foot) sections with an integrated wheel assembly that can be raised and lowered with a built-in hand crank or optional compressed air system. With the wheels down, ArmorGuard can be easily moved to reconfigure the work zone and can even be towed or pulled slowly along the road during mobile construction operations.

Are these technologies effective?

Recent studies have demonstrated that the introduction of new technologies into roadway work zones are having a positive impact on motorists, with over 70% indicating they slow down when they see speed advisories. Furthermore, well over 50% of drivers opted to change their routes when they received messages about work zone-related delays, especially when the messages contained specific information about exits and alternative roads.

Roadway work zones have come a long way from the oily smudge pots and red flags of 30 years ago, thanks in large part to members of ARTBA’s Traffic Safety Industry Division. The transportation construction industry is continuously taking advantage of new technologies to improve mobility and safety for workers and all roadway users.

There's also a work zone intrusion alarm. Details here.

Cyd Gorman, marketing manager, Transpo Industries