Trial of 3D lane markings for road safety

CASR is conducting a trial of a novel design of 3D-looking lane markings at selected sites around the Adelaide metropolitan area. This novel lane marking design aims at inducing motorists to become aware of a change in the road environment while they are transitioning into a low-speed area (speed limit of 40 km/h) with high pedestrian activity.

This trial is funded by the Australian Government through the Department of Infrastructure, Transport, Regional Development, Communications and the Arts.

Marking design – 3D-looking ‘dragon teeth’

The trialed lane markings are a 3D-looking variation of the so called ‘dragon teeth’. The markings comprise a series of simple triangle shapes located alongside both sides of the travel lane leading into the 40 km/h section. The triangles appear to be slightly floating over the road surface through a perceptual visual illusion.

The whole idea is to use this 3D perception to attract motorists’ attention and provide an effective visual ‘heads-up’ of an incumbent change in the road environment ahead.

Similar 3D markings have been successfully implemented in Singapore, particularly at boulevard-style entries to 30 km/h zones frequented by a large number of pedestrians — especially older people and children. A broader variation of other 3D markings are also used worldwide for speed mitigation or to convey warning messages.

Trial objective – Propose a potential tool for Movement & Place applications

The Movement & Place approach focuses on the main concept that the road design should clearly reflect its predominant and desired use – either movement of people and goods, or placing making activities located alongside a road.
Under a placemaking objective, the road purpose shifts from being a traditional conduit for traffic flow to becoming a ‘destination’. Therefore, the main priority is creating a safe and forgiving environment for VRUs by calming motor vehicle traffic and reducing their travel speed. Implementation of low-speed zones is a common practice to improve safety of VRUs when defining placemaking areas, with speed limits often being reduced to as low as 30 km/h. Nonetheless, low-speed limit zones may not be always promptly identified by motorists, resulting in traffic speeds to be higher than what desired.

This proposed design of 3D lane markings is expected to be well suited to complement and enhance the safety benefits of lower speed zones in areas with a high risk to VRUs through a dual approach.

• Traffic calming – The perceptual 3D marking is expected to induce a reduction in the travel speed of approaching vehicles through creation of a combined effect of channelisation and lateral friction.
• Improve awareness – The perceptual 3D marking is also expected to improve awareness of lower speed zone areas as well as improve speed compliance. This marking is perceived as three dimensional by motorists while they approach the entry to a reduced speed limit zone, therefore helping them to clearly identify that they are entering an area of the road network where the ‘placing’ roles of the road (i.e., pedestrian movements around business and social venues) becomes a priority over motorised vehicle movement.

Trial evaluation – Measure potential traffic calming effect

These novel 3D markings are being trialed at four sites around the Adelaide metropolitan area. Their installation is being conducted in collaboration with the Department for Infrastructure and Transport (DIT).

The evaluation of the proposed 3D lane markings will be based on the analysis of vehicle travel speeds. Speeds will be measured at each of the trial sites before as well as after the installation of the markings. Any changes in vehicle travel speed after the treatment installation will inform whether this treatment may induce a traffic calming effect. The potential effect of other factors, such as weather conditions, will be controlled and isolated during this evaluation.

Vehicle speed will be measured at three different locations - on the approach to the markings, immediately downstream of the markings, and in the mid-block of the 40km/h speed segment.

Project manager: Mario Mongiardini