I was wondering if any of you has much experience of using the Siemens Heimdall detectors for MOVA applications and if so how have you found them? I am considering specifying them for a MOVA roundabout but thought I would canvass opinion first!
I haven't used them myself but I do know that they're apparently the only overhead detector that is 'Approved' by the HA for use with MOVA and SCOOT. The AGD ones don't have approval but are equally as good.
I'd be interested to hear what people have to say also.
Writing on behalf of AGD Systems Ltd., I would like to point out that it is our understanding that there is no specification for above ground MOVA detectors to obtain approval for. We would be very keen to learn of the specification that the HA has used for issuing approval for the Heimdall detector.
The Heimdall publicity uses the wording 'advanced solutions' for SCOOT and MOVA. Then explaining that it uses a 24GHz planar radar, which I believe are available from other manufacturers. No mention of approval except EMC and Radio. Interestingly they refer to a trial for a SCOOT site in Winchester, where a video based detector unit was also tested with excellent results.
In Lancashire we are currently using one of the TrafiCam video detectors supplied and installed by Telent. This is currently employed as a stop line detector, but so far the result is very good, and I would certainly consider the same equipment (at a suitable site) for MOVA use. A free demonstration by the company is well worth a look.
Be aware that the drawbacks with any of these detectors is "occlusion" where the "view" of the lane to be monitored is obstructed by a large vehicle, and also the requirement for more than a simple paired cable to install it in the right place. Both may be a problem at a signalled roundabout, and MOVA does not function well if the detection is missing some of the traffic.
TAL16/99, (page 4 of the reformated TAL16/991version) "recommends" a number of circumstances where Above Ground Detection isn't used, including for MOVA.
The _Advisory Leaflet_ also says: "Cost benefit analysis suggests that it is not possible to use above ground detectors for MOVA at present because of the large number of detectors needed to cover the detection zones, additional mounting and in some cases ducting requirements." and is dated December 1999. Although no further guidance may have been issued, I would not consider myself bound by this advice eleven years on with much later technology available.