The SATT head office in Cape Town was visited in February 2013 to view their available products, inspect their manufacturing facilities, and to discuss SATT’s ability to manufacture conventional VAS, similar to the products available from Swarco Traffic Ltd in the United Kingdom.
SATT manufactures a wide range of electronic signs, which includes variable message signs, parking guidance systems and signs, as well as sport scoring systems and signs. Their range of variable message signs includes full size overhead freeway management signs to trailer mounted portable variable message signs and speed control signs, suitable for use in both urban and freeway environments (SATT, 2013).
Although SATT was found not to manufacture conventional VAS at the time of this research, the company was confident that they do have the capability in terms of knowledge, resources and facilities to do so.
SATT’s trailer mounted speed control sign, referred to as the Speed Sign Trailer (SST), is considered to be most similar to a conventional VAS in terms of its function and use. A typical example of the SST is shown in the following figure and the SST product brochure is included in Appendix F.
Figure 4-4: Speed Sign Trailer (SST)
(Source: SATT, 2013)
The SST is aimed at traffic calming within zones where roadworks are undertaken. The SST combines a static speed limit sign with an electronic sign and radar. The static sign denotes
the speed limit within the work zone while the radar detects vehicle speeds within the work zone, compares this to a preset threshold, and warns motorists exceeding this threshold to slow down.
The static speed limit sign is user changeable from 60 km/h to 80 km/h to 100 km/h. Speed thresholds can be set according to the static sign section through dipswitch settings. An upper threshold can be set, against which only the speed message is displayed, thus preventing motorists from using the sign to test the speed capabilities of their vehicles.
Flashing beacons are triggered once the speed threshold has been broken. The SST is lightweight and can be towed by a car or light delivery vehicle. It is easily deployed within roadworks or maintenance zones. The SST is powered by a battery bank and a solar panel that constantly charges the battery. The sign is lowered when in transit and is raised by a hydraulic hand actuated pump once in the position of deployment.
The cost of a typical SST in August 2013 was R 64 000, which excludes VAT and any associated delivery fees. SATT’s speed sign trailers carry a 12 month manufacturer’s warranty.
4.3.1.2.2 POLYCOMP
The Polycomp head office in Modderfontein (Johannesburg) was visited in October 2012 to view their available products, inspect their manufacturing facilities, and to discuss Polycomp’s ability to manufacture conventional VAS, similar to the products available from Swarco Traffic Ltd in the United Kingdom.
Polycomp manufactures a wide range of electronic signs, which includes variable message signs, parking displays and scoreboards. Their range of variable message signs includes from full size overhead freeway management signs, to trailer mounted, portable variable message signs and speed indicating display signs (Polycomp, 2013).
Like SATT, Polycomp was also found not to manufacture conventional VAS at the time of this research, but likewise the company was confident that they do have the capability in terms of knowledge, resources and facilities to do so.
Polycomp’s speed indicating display signs are considered to be most similar to conventional VAS in terms of their function and use. Typical examples of speed indicating display signs
are shown in the following figure and the speed indicating display sign product brochure is included in Appendix G.
Figure 4-5: Speed Indicating Display Signs
(Source: Polycomp, n.d.) (Source: Polycomp, n.d.)
Polycomp’s speed indicating display signs have been designed to increase driver awareness and to warn motorists when they are exceeding the applicable speed limit on a road. The use of these signs does therefore improve road safety for road users and reduce the risk of road traffic crashes occurring as a result of high vehicle speeds.
Speed indicating display signs can be used on most road types, for example national roads, urban roads, roads in residential areas, at schools or on the approaches to pedestrian crossings. The signs are also used by municipalities, large university campuses, mines and large factories that require speed limit restrictions.
The signs can be permanent installations, fixed to a sign post, or movable, for example mounted on a small trailer. The signs are supplied with a choice of conventional (electrical feed) or renewable energy (wind or solar) power sources.
The operator can set the sign’s trigger speed by using a laptop via a RS232 communications port. If an oncoming vehicle exceeds the pre-set speed limit, the sign unit will show the speed of the approaching vehicle, activate two flashing beacons for two seconds indicating to the motorist that he had exceeded the speed limit.
The unit price of sign post mounted speed indicating display signs range from R 27 000 (excluding smiley face) to R 32 550 (including smiley face). Optional extras include the following items:
Solar panels = R 8 500
Deep cycle batteries = R 5 000 High quality charger = R 2 200
Trailer mounted alternative = R 22 800
The above prices were obtained from Polycomp in August 2013. They exclude VAT and any associated delivery fees. Polycomp’s speed indicating display signs carry a 12 month manufacturer’s warranty.
Polycomp also offers customers service level agreements to ensure that display signs are serviced on a regular basis. Regular services assist to keep display signs clean and well ventilated. Display signs tend to overheat if not adequately maintained. Overheating tends to cause key parts of the electronic components to deteriorate at a faster than normal rate, which usually leads to the failure of the display signs. This could be a costly expense to repair or even replace.