National Work Zone Awareness Week 2023

Calling Time on Unnecessarily Putting Road Workers at Risk

Practical and affordable steps to reduce road worker’s exposure to risk.

The National Work Zone Awareness Week (NWZAW) that runs from April 17-21 this year quite rightly shines a light on the need to increase safe driving around highway work zones. The campaign is a joint initiative between the American Traffic Safety Services Association (ATSSA), the Federal Highway Administration (FHWA) and the American Association of State Highway Transportation Officials (AASHTO) and is supported by the State Departments of Transport (DOTs).


While there are many work programs that depend on road workers carrying out their work with only the protection of traffic cones, there are also some work programs that are putting lives at risk when there are safer alternatives. With the increase in Advanced Driver-Assistance Systems (ADAS) including Lane Keep Assist/Lane Departure Warning systems now in all new vehicles, there is increased pressure on road agencies to improve the quality of road pavement markings. These safety vehicle ADAS technologies rely upon good quality visible pavement markings day & night in dry & wet conditions.


The introduction last year of MUTCD mandatory minimum standards of retroreflectivity of pavement markings was also a critical step in the right direction to improve safety for all, but particularly for vulnerable road users to ensure markings are visible in low light and night-time driving conditions. There is now a greater demand for Mobile Retroreflectometers since Sept 2022 when the Federal Highway Administration (FHWA) published the final rule for pavement marking minimum retroreflectivity in the Manual on Uniform Traffic Control Devices (MUTCD). These rule changes require agencies to plan annual assessments of their main longitudinal pavement markings to ensure compliance with the mandatory requirements for minimum retroreflectivity levels and avoid expensive legal torts for non-compliance.

As a result, Road Agencies including Departments of Transport’s, Cities & Counties are now required to maintain pavement markings on their road networks to meet minimum standards of visibility. This requires the use of pavement marking retroreflectometers to measure the night retroreflectivity and day contrast of pavement markings. Despite the sheer volume of roads to be measured annually in the USA, it is estimated that sales of manual handheld retroreflectometers far exceed vehicle mounted mobile retroreflectometer sales by a factor of over 10! When using these handheld retroreflectometers, traffic management including lane closures should be required with road workers manually holding the devices over each pavement marking to record sample measurements.


However, there is a solution and road agencies can avoid these high traffic management costs & the unnecessary risk to road workers by opting to use vehicle mounted Mobile Retroreflectometers (MRUs). Vehicle mounted Mobile Retroreflectometer Units (MRUs) are attached to survey vehicles and can operate at traffic speeds and automatically perform continuous measurements on all the pavement markings & not just a small section/sample of pavement markings. All of this is achieved with the same level of accuracy and repeatability as handheld retroreflectometers, but without the need for lane closures & traffic management & the unnecessary risk to road workers.

RetroTek-D Front Mounted Retroreflectomer (MRU)


There are two types of MRUs available – vehicle Side-Mounted & vehicle Front Mounted MRUs. Front mounted MRU systems are more efficient than side-mounted MRUs as they survey the long lines on the right & left of lane travelled including any critical safety center in-lane markings /symbols, in the one pass. Side Mounted MRUs are limited to only surveying the longitudinal line markings to one side of the survey vehicle at a time. This effectively means that critical safety center markings such as directional arrows, transverse lines, cross walks, safety warnings, symbols, etc. must still be measured manually with handheld retroreflectometers, reverting to requiring lane closures, traffic management & increased safety risks to road workers.

“Tandem” Two Mobile Retroreflectometers – One on each side
Side Mounted secured with Suction Vacuum Pads

As an alternative to front-mounted Mobile Retroreflectometers that are capable of measuring all pavement markings across the full lane width including road RPMs, some side-mounted MRU manufacturers are suggesting using a side-mounted system on each side of the vehicle, sometimes referred to as “Tandem” systems. This effectively means having two measurement devices attached with straps/suction vacuum pads, one to each side of a vehicle protruding wider than the vehicle width, in order to measure longitudinal pavement markings on the left and right of the vehicle. The safety aspect of this approach for the survey operator and other road users is highly questionable for several reasons as the width of the vehicle is increased significantly and the operator has to monitor 2 MRU sensors while driving, which can lead to driver distraction and potential incidents and problems when encountering wide & narrow lanes, and narrow lanes at toll booths. The risk of damage to these expensive MRU units is also increased.

LED Versus Lasers:

The RetroTek front mounted MRU uses safe LED lighting sources as opposed to lasers. Laser projects a narrow line onto the road and are particularly hazardous as light is emitted in a tight beam that does not grow in size at a distance from the laser. Narrow lasers may require complicated levelling systems to compensate for road surface unevenness, vehicle bounce or shift in vehicle set-up. As a result, the same degree of hazard to the human eye can be present both close to and far from the lasers source. By contrast, LED lighting is rapidly becoming a standard feature on most new vehicles on our roads. The RetroTek LEDS emit a deep beam of light that covers approx. 3 yards deep on the road surface and with a Field Of View (FOV) of approx. 16 feet wide. LED beams can compensate for unevenness & bounce, within the software algorithms.

RetroTek-USA Inc is a subsidiary of RMS Ltd, combining the latest developments in LED and camera technology to improve the safety of pavement marking retroreflectivity surveys. The innovative research and development have produced the safest vehicle mounted Mobile Retroreflectometer (MRU) available on the market and now operating globally.

At RetroTek-USA we fully support National Work Zone Awareness Week (NWZAW) and we believe that road agencies can do more, within their control, to ensure the safety of road workers.

Investing in the safest, most efficient & environmentally friendly Front Mounted Mobile Retroreflectometers (MRUs means moving away from the heavy reliance on handheld retroreflectometer units, incurring expensive lane closures & traffic management costs and most importantly of all removing road workers from the road and risk of accidents and death.

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