Giving oral evidence to a Transport Select Committee hearing into the work of the agency, trade union side secretary Kevin Warden said VOSA's unions remained "deeply concerned about privatisation," as the incentive for profit undermined a commitment to road safety.
He said VOSA strongly regulated the testing for cars and light vehicles, but inspectors often found that 25 per cent of vehicles had been incorrectly tested by the private sector.
Given the commercial pressures of running heavy vehicles, he said there was an obvious concern that the same would happen if heavy vehicle testing were to be undertaken by the private sector.
He added that one trade body, the Freight Transport Association, had submitted 555 vehicles for a service and found that 27 per cent would have then failed their MOT.
Asked if staff employed by the private Authorised Testing Facilities should be able to conduct MOT tests for heavy vehicles, Warden said he feared the profit incentive would lead testers to cut corners, whereas VOSA staff are motivated by road safety, rather than profit.
Warden added that heavy vehicle testing plays an important part in road safety enforcement, as test results feed into VOSA's enforcement targeting system, known as Operator Compliance Risk Score.
VOSA uses the OCRS system to decide which vehicles should be inspected. OCRS is used to calculate the risk of an operator not following the rules on roadworthiness (the condition of its vehicles) and traffic (eg drivers' hours, weighing checks). An operator get points when a test or inspection finds a defect or infringement of the rules. A high OCRS means the vehicle is more likely to be stopped for a roadside inspection.
Operators being allowed to test their own vehicles, as being advocated by some of the trade associations, would add further pressure to pass vehicles as it would reduce the likelihood of those vehicles being stopped at the roadside, he said
While acknowledging that ATFs can play a supportive role in supplying suitable sites for VOSA staff to test heavy vehicles, Warden reiterated the unions' view, as set out in a letter to the then Transport Minister Mike Penning, that there should be a strategically located 'backbone' of VOSA test facilities supplemented by ATFs providing additional testing capacity.
Later in the session, trade union side assistant secretary Gary Washer also criticised the decision to reduce funding for policing and the enforcement of standards for foreign HGVs as well as the way the funding is collected with money from fixed penalties often going straight to the Treasury.
Lastly, both witnesses pointed to the increasing burden of costs felt by the organisation in various areas, such as a reliance on external legal advice to prove cases.
Watch the evidence session at http://bit.ly/vosatesting