System

• The system based on laser curtain, consisted of three laser measurements systems (LM210) produced by Sick [@]. The systems were mounted above each lane. This measurements (which have some overlap) were combined in software, especially developed b by QFree [@], as part of their multi-lane Electronic Fee Collection system. This system was able to produce accurate height and width measurements.
• The system based on inductive loops also consisted of three subsystems, placed in the road surface in the centre of each lane. This system was able to produce accurate length and speed measurements.

Both results were compared with each other, and in case of inconsistencies, a human operater could overrule both systems based on the images of an overhead camera, which were also recorded.

The results of the laser based system were of a prototype, and are not free available. The actual measurements of the inductive loop system can be downloaded from this site:
 

• ILSRecord.zip (2 MB)

        Timestamp,         DateTime,      OrgDateTime,ResCode,Lane,Direction,Speed,Length
20000228113001651,20000228113000650,20000228113001960, 000000,   3,        1,   93, 15.31
20000228113002339,20000228113001840,20000228113003150, 000000,   2,        1,  113,  4.51
 
 

1.	Location	Dutch highway A12 between Woerden and Utrecht.
2.	Period	Samples between 28 February and 28 April 2000.
3.	Circumstances	As varied as possible (snow, rain, low sun, congestion, high and low density).
4.	Capacity	A wide and straight 3-lane road, which could handle 7260 vehicles/hour.
5.	Speed	Standard Dutch regulations, 120 km/h for cars, 80 km/h for lorries.
6.	Measurement system	Two systems, one based on inductive loops, the other on a laser curtain.

The set is unique in its level of detail. By combining two systems, much higher accuracy than normal could be achieved. For instance, this system was able to detect most of the passing motorcycles.