Discrepancy in driving theory handbooks

HOW LONG does it take to bring a car or motorcycle travelling at 100km/h on a dry road to come to a complete stop?

According to the Driver Theory Test book(2008), the average car or motorcycle will stop after 80m. However, the Rules of the Road (2007) reckons a distance of just 77.7m is required. A similar discrepancy arises in relation to a stopping on a wet road.

The correct answers are those in the Rules of the Roadand, following inquiries by The Irish Times, the RSA is to temporarily remove both questions from the driver theory test.

“Until the matter is clarified to our satisfaction the two questions have been temporarily rem-oved,” an RSA spokesman said.

He said the most likely reason for the discrepancy was that the figures had been “rounded”. He said an “update of the DTT book and CD is planned for the end of April. . . any corrections will be in place by then”.

The 2007 DTT book had a figure of 70m to stop a vehicle at 100km/h on a dry road and was revised to take account of an update for the Rules of the Road.

Frank Cullinane, advanced driving instructor registered with the RSA and former garda with 30 years’ driving experience spotted the discrepancy.

He believes many Irish drivers lack the skills to steer, brake and observe at the same time.

He also thinks the stopping distances in the Rules of the Road2007 book may be misleading by suggesting a motorist can drive closer to a vehicle in front than they should on roads with higher speed limits.

He made this claim after carrying out hundreds of emergency braking manoeuvres at 100-120km/h under testconditions and discovered he “could not match the stopping distances in the Rules of the Road”.

The RSA commissioned the Transport Research Laboratory (TRL) in England to research average stopping times when it revised the Rules of the Roadin 2007. Stopping distances in this book are the same as those in the UK. Stopping distances in the Rules of the Roadassume emergency braking, although this is not specifically stated.

The theory test is operated by Prometric, which tests roughly 170,000 candidates a year. There are 1,300 possible questions and 35 out of 40 must be answered correctly to pass.

The DTT book is revised regularly to reflect changes in rules and in law, such as metrification or the introduction of penalty points.