5500-mile marking assessment reveals four simple ways to make automated driving safer.

By far the most common issue. In such areas, the right edge line is stopped. Often leaving the merge area open and void of markings. Once the vehicle loses sight of the right line, it spots the merging lane’s edge line and attempts to center on that marking. Basically, splitting both the main travel-way and the merging. This can cause the vehicle to shift its position to the right abruptly. At times the vehicle’s cameras will identify the seam in the pavement as a lane delineator and maintain its centering of the proper lane. The simple fix is to extend the markings, in skip form, through the majority of this unmarked area.  However, an area at the end of the merge must be left unmarked of skip line so that a merging semi-automated vehicle will know it can merge into the adjacent lane. 

Work-zone tapers/merges in lane drop

When these tapers are left unmarked, this scenario can be very dangerous. Due to the short duration of some work-zones, often time contractors will not mark the taper with the continuous marking upon which these systems rely. Cones, barrels and even concrete barriers are placed over the markings. Additionally, the existing lane line skips are left in place. So, these markings or the vehicle’s rails go straight into the cones, barrels, barrier wall or work-zone and the vehicle is sure to follow! The simple fix is to apply a temporary lane marking along with the merge and mask a portion of the existing skips. This will cause the system to merge properly and safely out of the dropping lane and into the merge lane.

Median turn lanes (cross over)

Many communities have center medians in their roadway system for turn control, beautification or directional separation. These medians are often marked with a yellow edge line. We have found that in some cases, if the edge line marking has a long slope into the turn lane, and the turn lane’s white edge line is delayed or missing, the vehicle will respond as it does on the entrance ramp’s acceleration lane described above. The simple fix is the addition of skip line-markings filling the gap between the beginning of the turn lane to the solid white edge line. 

Lane divergence and add

This is when a roadway’s lane count increases, let’s say from three to four lanes. Considering the lane is added to the left edge… the left edge line tapers left and, in some designs, the right white skip line ends. For a moment, the vehicle only sees the left edge line tapering to the left and the adjacent lane’s edge markings on the right. Then suddenly the skip line appears in front of the confused vehicle splitting the new and existing lanes. The vehicle now must choose what lane it is to center on. All the while, the vehicle is abruptly shifting left and right across the travel ways. A simple fix is the continuation of the white right skip line and the extension of the new lanes white skip into the tapering yellow edge line.separation. These medians are often marked with a yellow edge line. We have found that in some cases, if the edge line marking has a long slope into the turn lane, and the turn lane’s white edge line is delayed or missing, the vehicle will respond as it does on the entrance ramp’s acceleration lane described above. The simple fix is the addition of skip line-markings filling the gap between the beginning of the turn lane to the solid white edge line.

All these issues could be corrected by a simple extension of the solid or skip lane lines. If these fixes were at great cost, or only served the machine-driven vehicles, we would be best to call for solutions by the auto industry. However, the cost is minimal in comparison to other roadway infrastructure components. And these alterations will likely enhance the safety of human drivers.

Although the autopilot system struggled in these areas as well as a few more, like the complex markings of a diverging diamond or an area of severely diminished markings, it performed extremely well overall. It even performed beyond our expectations under certain conditions. We believe it to be a safe and effective assistance system to the driver as long as the dependence or expectations of the driver are not too great.

For more information on the findings of the Measure Across America Project, connect to PPPCatalog.com/MAAP and monitor for periodic update releases.