[SystemSafety] Wheel detachment from a moving car

[David Crocker]

My partner has a nasty near-accident on Tuesday. While travelling on a
dual carriageway at 60mph, she became aware of a new noise from the
vehicle. Shortly afterwards, the front nearside wheel detached and she
saw it roll into an adjacent field. Fortunately the car did not tip
over. She is a skilful driver, so she allowed the vehicle to decelerate
without using the brake. She was not rear-ended, and when at a slow
speed she drove it into the adjacent grass verge. She was shaken but
unharmed. The car is beyond economic repair because the steering
assembly and other parts are wrecked.

She had driven 500 miles since having the tyre on that wheel replaced.

This got me thinking:

1. How often do wheels detach from cars while travelling? Are there any
figures recorded? Have any fatalities occurred as a result?

2. Why is there no requirement on manufacturers and fitters to use
locking wire, a cotter pin, or some other mechanism to ensure that the
wheel nuts cannot come off? I notice that some HGVs do use locking wire
on the wheel nuts.

-- 
David Crocker, Escher Technologies Ltd.
http://www.eschertech.com
Tel. +44 (0)20 8144 3265 or +44 (0)7977 211486