Delta Roadsensor Retroreflectometer vs Retrotek Retroreflectometer

Comparing the Delta Roadsensor Retroreflectometer to the RetroTek Retroreflectometer

Technology developments by vehicle manufacturers are focusing on safety measures that will impact on the road marking industry. Advanced Driver Assistance Systems (ADAS) will increase pressure on Road Authorities to improve the quality and consistency of road markings to support new safety systems, including Lane Departure Warning. These ADAS systems will be in 73% of all new cars by 2023, according to industry analysts. These advances in driving technology are facilitating a more standardised approach to uniform road markings internationally, in order for ADAS enabled vehicles to function efficiently.

Delta LTL-M Dynamic Retroreflectometer

Delta Retroreflectometer side mounted

RetroTek-D Retroreflectometer

Delta LTL-M Retroreflectometer vs RetroTek-D Retroreflectometer lane measurement

“…the first retroreflectometer with the capability to measure a full lane in a single pass…”

Delta LTL-M retroreflectometer – single line measurement

The Delta LTL-M retroreflectometer accurately takes retroreflectivity measurements at both day and night, with a narrow viewing field – allowing an operator to cover a line with some driving skill required.

The RetroTek-D takes a new approach to retroreflectivity measurement. It’s the first retroreflectometer with the capability to measure across a full lane width in a single pass. That’s both left and right lane markings along with any central lane markings & symbols. This is drastically reducing the time taken to complete a road survey by up to 50% and is therefore reducing the fuel costs associated with road surveys by 50%. Side mounted systems cannot do center lane markings symbols without lane closures and traffic management.

Delta Mobile Retroreflectometer front view

Delta retroreflectometer precision driving

The Delta retroreflectometer viewing field range requires the operator to remain close to the line being measured. This means that a fair amount of driving skill and attention is required in order to obtain accurate and complete survey results.

The RetroTek-D obtains complete survey results while the car is situated in a normal lane position. This makes surveys much safer for the single operator/driver and other road users with no requirement for precision driving close to the edge or centre lane lines. The RetroTek-D software algorithms continuously search and monitor for the lines and centre markings and adjust accordingly leaving the drive/operator to concentrate on driving.

Front Mounted Retroreflectometer vs Side Mounted

The Delta unit is fixed to the side of the survey vehicle. Unlike many competitor side mounted units, the Delta LTL-M is a hard-mounted system, eliminating the hassle and risk factors associated with mobile systems that rely on suction cups and strapping for use. One of the drawbacks of side mounted units is that they do present an increased risk to passing traffic due to the need for them to protrude from the side of the vehicle in order to be in range of the road markings. The Delta system measures at a distance of 6m ahead of the sensors at a height of 10cm above the ground.

Delta Mobile Retroreflectometer front view

The RetroTek-D is an innovative front mounted retroreflectometer unit. This system is mounted using a standard front square tow hitch on the survey vehicle. Due to the fixed nature of this unit, there are none of the safety or vibration issues associated with competitor units that rely on suction cups or straps. It does not protrude from the side of the vehicle to endanger other road users. The RetroTek-D enclosure has ~ 8”+ (200mm) ground clearance while carrying out a survey, double the clearance of dynamic side mounted systems ensuring sufficient clearance for kerbs, parking stops, speed ramps etc. When not operational, it can be raised even further to provide even further protection. The RetroTek-D retroreflectivity conforms to 30 metre geometry & takes measurements at a distance of 12m ahead of the sensors.

Overhead Camera

The Delta LTL-M uses an overhead camera to support visual inspection of problem areas during reporting. The issue with using an overhead camera is that it may not quite capture the view that the retroreflectometer is seeing due to the difference in viewing angle, which could lead to difficulties visibly identifying the cause of road markings failing to meet requirements.

LED Projector system and Integrated Camera

The RetroTek-D uses a camera that is integrated within the front mounted unit. The images captured with this HD camera are used to support visual inspection during reporting. With the camera being mounted much closer to the road than with an overhead camera, images obtained provide a very clear picture of the condition of road markings.

Other key features of the Delta Retroreflectometer vs the RetroTek model

Both the Delta and RetroTek systems are capable of carrying out surveys at normal road speeds, eliminating the need for road closures/traffic management.

Independent tests have verified that the RetroTek-D accurately measures in day or night the night visibility RL (coefficient of retroreflected luminance) of pavement line/striping markings to CEN En 1426 & ASTM E 1710 & as accurate as hand held retroreflectometers. The system also counts the presence and absence of Pavement Markers (RPMs)/ road studs and centre median barrier reflectors. RetroTek-D uniquely measures the retroreflectivity (RL) of both right and left longitudinal lines (edge and centre lines) and centre lane marking/symbols. This is not possible for side mounted systems without road closure/traffic management & multiple survey passes.

Both systems can accurately measure the daylight contrast ratio between the road surface and the road markings. The RetroTek-D has built-in auto-exposure to compensate for bright sunlight, shadows, road glare and vehicle bouncing from uneven road surfaces and driving behaviours (accelerating/braking).

The Delta and RetroTek systems both use GPS to accurately record the locations where measurements have been taken, and where markings have not met retroreflectivity requirements. This allows road maintenance authorities to efficiently plan road marking maintenance efforts.

Both systems offer repeatability of +/-3%, and reproducibility of +/-5%, making them extremely competitive to handheld instruments.

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