Apr

Take trucks into account

2011-04-01 19:44
See Case Study One in this article - are we really taking trucks on suburban roads into account?

Road safety is not just about having skilled drivers and roadworthy vehicles on our roads. What also plays a major part is road safety engineering and yet there are some spots on our national, urban and rural roads where the road engineering causes rather than prevents truck accidents and incidents. One such spot is the infamous R28/N14 Pinehaven intersection near Krugersdorp. Another is a traffic calming circle in Honeydew writes Patrick O’Leary.

Most people , perhaps understandably – confuse the term ‘˜road safety engineering’ with the actual building of roads from a structural and materials composition point of view. There is far more to it than this. When designing and building a road, apart from construction methods, road safety engineers also have to concern themselves with aspects such as the camber of the road, general road layout, visibility issues, road junction safety and other such issues.

A major factor taken into account by engineers when designing a road is the speed limit of trucks, cars and other road users. You won’t for example, find hair-pin bends on a national intercity highway where the speed limit is 120kph. You will find them on mountain passes where the speed limit varies between 40kph and 60kph.

Once a road is built, the road safety engineers then ‘˜decorate’ the road with a variety of appropriate speed and warnings signs, road markings, rumble strips – such as at approaches to toll plazas to get vehicles to slow down or centre aisle rumble strips to prevent driver fatigue on long routes – and many other practices to ensure the safety of road users. It is a science on its own and all this is done to prevent road crashes by better planning and more safety conscious design of the road network.

After the road is built, marked (painted), sign posted and opened for use, the authorities are then supposed to monitor the road to identify danger spots through recording incidents and accidents. By identifying and treating hazardous spots, road safety can be significantly improved. If, for example, you get a lot of vehicle roll-overs on a particular bend, remedial action may be to change the camber of the road on that bend. The solution could lie in engineering rather than driver remedial action.

Traffic calming

Some years ago, ‘˜traffic calming’ bumps and circles found their way into the suburbs and residential areas of our cities where the speed limit for all vehicles is 60 kph. By monitoring certain roads, authorities found that many motorists go way beyond this limit thus endangering other road users, pedestrians, cyclists, et al. There are enough horror accidents on record to prove this as truth.

The remedial action was to install these traffic calming bumps and circles which are now in wide-spread use around the country. Some of the circles were also put in place to speed up the flow of traffic at intersections by replacing stop signs with yield signs for incoming traffic to the circle. Not a bad idea as it is also done in many overseas countries.

While they certainly do serve a constructive purpose if positioned correctly and constructively, FleetWatch has a gripe , and here it is:

From what I have seen around the suburbs of Johannesburg, the design and positioning of many traffic circles do not take into account the dimensions of trucks and their ability to manoeuvre round the circle without having the rear trailer wheels mount the circle. An interlink combination is 22m long and I doubt whether there is one traffic calming circle that takes this into account. This can have dire consequences on truck operations and the accompanying photographs show two such incidents.

Case 1

Huge delays in traffic as the mess was cleaned up...

Huge delays in traffic as the mess was cleaned up…

and the load fell off!

and the load fell off!

The truck leant to the left...

The truck leant to the left…

The truck came down Boundary Road to the yield sign and tight circle...

The truck came down Boundary Road to the yield sign and tight circle…

FleetWatch contends that this was NOT the driver's fault!

FleetWatch contends that this was NOT the driver’s fault!

In Honeydew, there is a traffic circle situated about 50 or so metres off Beyers Naude Road at the intersection 2of Honeydew West and Boundary Road. I’m not exactly sure whether it was put in as a traffic calming circle to force reductions in speed or more as a method to facilitate the better flow of traffic at that intersection via allowing for yield rather than stop signs. Probably the latter but whatever the reason, it causes havoc for trucks.

The truck pictured here was delivering chipboard to Ferreira’s Hardware & Buildware. The driver told me he somehow missed the entrance to Ferreira’s and went around the block to re-approach the Ferreira’s entrance. He came down Boundary Road and tried to turn round the circle into Honeydew West to get back to Beyers Naude. The turn was too tight and the rear wheels of his trailer mounted the circle with the result that the trailer leant heavily to the side and the load fell off.

Without going into the issue of load securement or applicable strapping , which I think also played a role in this incident – the point here is that no interlink should be allowed to travel down Boundary Road , or any other incoming road towards this circle. They are going to get stuck, lose their load or even fall over (if going into the circle too fast). And all three have happened as a resident from one of the nearby houses told me at the scene. The driver of this truck did not know the area and when driving round the block, was unaware that he was going to come up against a traffic circle. A sign prohibiting interlinks from travelling on any road leading to that circle would have prevented all this.

Case 2

Case 2: There is no ways this rig can get around this circle without the wheels mounting it. Signs restricting trucks from going down roads towards such islands should be erected at appropriate places to prevent incident snarl ups.

Case 2: There is no ways this rig can get around this circle without the wheels mounting it. Signs restricting trucks from going down roads towards such islands should be erected at appropriate places to prevent incident snarl ups.

The second case pictured here happened close to the first one. Just recently, a traffic circle was built on C.R. Swart Drive, again about 50 metres off Beyers Naude Drive. Like the first one, it was probably built more to facilitate traffic flow with yield signs for traffic from incoming roads. However, as the pictures show, the trailer tyres of the truck coming in from Taurus Street mounted the circle.

Once again, this demonstrates that very few traffic calming circles take into account the turning radius of trucks , and this truck-tractor/ semi combination is shorter than an interlink.

FleetWatch suggestions

By highlighting these two incidents, FleetWatch urges all road authorities to address the situation in their areas. Here are our suggestions: When planning new circles, always take into account the turning radius of trucks when designing them. And if trucks of a certain length cannot be accommodated, then signs should be erected at suitable points diverting trucks away from that spot.

 Very few traffic calming circles take into account the turning radius of a truck... signs need to be erected prohibiting trucks of a certain length from using roads leading to a circle.

Very few traffic calming circles take into account the turning radius of a truck… signs need to be erected prohibiting trucks of a certain length from using roads leading to a circle.

For existing circles such as the two mentioned in this story, all circles should be investigated for their suitability to accommodate the safe passage of trucks and signs should be put up prohibiting trucks of a certain length from using the roads leading to the circle. That interlink should never have been allowed near the circle in Case 1.

The agitation of going a longer route is nothing compared to the accumulated losses operators incur through incidents such as this one.

In this case there was load damage, vehicle downtime, costs for bringing in a forklift to reload the goods plus reposition the shifted load on the front trailer of the interlink, customer dissatisfaction through late delivery , and that’s just touching the surface. There are many other hidden costs. Of course, the traffic congestion, time loss and agitation to other road users must also be factored in.

I contend that in this case, it was not the driver’s fault. Sure he got all the blame for holding everyone up but it was not his fault. He was a victim of poor road safety engineering practices.

If operators have other incidences such as this, please let us know so we can alert the roads authorities to review and remedy the situation. Email the editor , preferably with photographs if possible – at fleetwatch@pixie.co.za.

Tags:
COMMENT ON THIS STORY
0 comments

Add Your Comment

twenty − sixteen =