Minibus taxi drivers brake for speed beep

File Photo
File Photo

A loud warning tone activated when speeding has triggered a dramatic improvement in minibus taxi driver behaviour.

Researchers at the Stellenbosch University’s Department of Electrical and Electronic Engineering have evaluated the efficacy of the audible warning system in reducing speeding and improving speed compliance by long-distance minibus taxis.

“We found that the speed-triggered warning tone had a positive impact on speeding behaviour for taxis from the R61 between Beaufort West and Aberdeen‚ both when applied at an audible level that can be drowned out by a radio‚ and an even greater impact at a loud level‚” says senior lecturer in the Department‚ Dr Thinus Booysen‚ who conducted the study with Nelson Ebot Eno Akpa from the same department‚ and Prof Marion Sinclair from the Department of Civil Engineering. They received support from MiX Telematics‚ TomTom‚ and MTN.

“The impact of the loud speed-triggered warning tone on speeding is significant – usually‚ for 72% of the trips the taxis spend over 80% of each trip over the speed limit.

 “With the loud warning tone‚ this figure was reduced to only 20% of trips‚” Booysen said in a statement.

 He said that the warning tone was set to activate after driving above 110 km/h for 10 seconds‚ and that before activation‚ the mean speed of 40% of trips were above 120 km/h and 85% above 110 km/h.

 Although the speed limit for taxis is 100 km/h‚ many drivers think it is 120 km/h. Booysen said they decided on 110 km/h to make sure there isn’t too much resistance to the warning system.

 “We tested the warning tone at two volumes: one that could be drowned out by loud music‚ and one that could not be ignored.

 “The impact of the audible warning tone was stark: With the loud activation‚ the mean speeds of all of the trips completed were below 120 km/h‚ and only 40% of trips had a mean speed above 110 km/h.

“Time-based speeding frequency dropped from 81% to 60%. Although less pronounced‚ the soft tone also resulted in a reduction in speeding frequency to 70%.”

 Drivers reverted to their normal driving after the researchers remotely deactivated the warning tone (the drivers weren’t able to turn it off themselves).

The monetary perk of safe driving was quickly evident.

“When compared to the normal driving we observed‚ the speeds driven during the warning tone activation lead to a 30% improvement in fuel efficiency‚ which means a driver can increase his remuneration for the return trip between Cape Town and Mthatha with over R1‚000 by keeping to the speed limit‚” he said.

 In 2015‚ a driver was paid R500 for a round trip‚ and received a fuel expense of R3‚500.

Booysen said it was important to conduct the study‚ as previous speed compliance and road safety interventions‚ such as the average speed enforcement (ASE) haven’t had the desired effect as far as taxis are concerned.

“Despite the multitude of evidence that ASE significantly reduces speeding in developed countries‚ and despite it seemingly working in South Africa for passenger vehicles‚ our analysis of the speeding patterns showed that the taxi drivers appear oblivious to South Africa’s first ASE on the R61 between Beaufort West and Aberdeen.”