Increasing Road Safety Through Zero Traffic Impact.
A key benefit of using Mobile Laser Scanning (MLS) for road and rail corridor surveys is the significantly increased safety of the system compared to conventional surveying techniques
A key component in the planning and execution of conventional surveys along road and rail corridors is traffic management planning. Traffic management plans result from Job Risk Assessments which identify the major hazards and dangers of working in exposed areas along the corridor. The traffic management plan aims to eliminate or minimise these risks to personnel by incorporating some or all of the following actions.
- Blocking of traffic lanes.
- Placement of barriers and signage.
- Traffic Management personnel to manage traffic flow.
- Survey operations to be conducted in identified 'low flow' traffic periods.
Traffic management costs represent a significant proportion (commonly more than 20%) of budgeted costs for road and rail surveys.
MLS is an inherently safer method for corridor surveys, as:
- Data acquisition can be completed faster than conventional surveys requiring less personnel to be exposed to a dangerous workplace for much shorter periods.
- Personnel can remain inside the working vehicle during the data acquisition phase.
- Large portions of the survey can be carried out at traffic speeds, minimising the requirement for traffic management.
Using standard MLS procedures, the working vehicle only needs to slow down during the survey when it passes the control targets that have been placed in the road (or on the rail). These control targets enable the “point cloud” collected by the MLS to be transformed into the local mapping system. The working vehicle slows to walking speed at these targets to ensure that they are easily identified in the point cloud. During this process there are risks to the working vehicle from traffic approaching from behind that are not expecting the working vehicle to slow. Traffic management plans incorporating the use of “shadow” vehicles and “tailing” vehicles have been used to warn oncoming motorists of the requirement to slow during this measurement phase.
In order to further improve the safety of MLS surveys on roads and rail, McMullen Nolan have implemented a new approach to survey control, called Zero Traffic Impact (ZTI). This technique enables the entire MLS survey to be completed at road speed, without slowing for targets. There are two key aspects to the ZTI – control spacing and control targeting.
ZTI uses a proprietary technique that enables the control targets to be spaced further apart than standard MLS surveys. Reducing the amount of control required to maintain accuracy, provides cost savings and time savings in establishing control and further speeds the data acquisition process.
In addition, ZTI incorporates a new approach to control targeting. Instead of using discrete control points, ZTI can uses “areas” of control, which are established along the corridor. Having a larger “area” of control enables the post-processing software to match the MLS point cloud with the established control over a large area. Discrete points no longer have to be identified in the point cloud. The real benefit of this approach is that the working vehicle does not need to slow as it passes the control. Using ZTI further speeds data acquisition and minimises the need for shadow and tailing vehicles.
ZTI enables McMullen Nolan to carry out MLS surveys at traffic speed for the entire survey (no slowing) with zero access to the road or carriageway for control. The ZTI approach further enhances safety, cost and speed of data capture. The ZTI method has been used for the Kwinana freeway and Tonkin highways in WA with excellent results. This approach coupled with the McMullen Nolan’s proprietary developments represents a significant advantage over other MLS systems.
McMullen Nolan is excited about the future of Mobile Laser Mapping. They are pleased to offer a full service to end-users, or work as a “Mobile Laser Scanning” service provider to other Survey companies. Access to McMullen Nolan MLS will enable these Survey companies to offer their customers a greater range of technology and measurement solutions to meet their needs.
For more information on McMullen Nolan Mobile Laser Scanning, please contact:
John Nolan (08) 6436 1554.
Rod Eckels (02) 8084 5524
