When they are busy they have 3 vehicles per lane getting tested. First part checks your lights, horn, seat & seatbelts, etc, next up is the rollers to test your brakes & shocks then finally onto the ramp to check underneath plus all the suspension & steering.
A full test takes around 15-20 minutes so the ramp is up & down 3-4 times per hour. There is a car on it nearly all the time, when one drives off another drives on - like a production line. Then the test equipment moves the suspension about quite violently to test for play & this would give the ramp a hard time as it is in the raised position when this is happening.
They used to use a pit for this but changed to ramps quite a few years ago.
I would imagine that those ramps would be very expensive with all the extra test equipment fitted. But they do make quite a bit of money - if they test 4 cars per hour at £30.50 per car, 12 hours a day, 6 days a week = £8784. Wouldn't be long paying for a new ramp!
It was quite a good system when they had experienced time served mechanics doing the testing. But now they are employing young guys straight from completing their apprenticeship who lack the experience & common sense to test a car properly, especially older cars. If a car isn't doing exactly what it says on the computer it's a fail, no middle ground at all.
I've had more than one argument with one of the young testers about items they've failed, but I always get one of the more senior testers over for a second opinion & I'm always proved right!