It's a common occurrence and not indicative of a problem, though it can appear more severe in some vehicles depending on how they are used, the design of their exhaust systems and other factors.

WSJ: How to Keep a Deer Out of the Headlights

"I had the problem a few years ago at the 2002 Commonwealth Games and never thought there would be a re-occurrence, " Pavey explained.

BBC: Jo Pavey receives assistance after the Great North Run