Speeding is quoted as being responsible for less than 5% of accidents, a more credible third is for not being observant.
On the road between Kilmarnock and Ayr there has been some serious accidents, including the death of a policeman responding in the middle of the night to an incident in a local town, caused because someone decided to cross the dual carriageway. I asked my MP why these crossings weren't closed as they have been in other accident black spots in Ayrshire, which have been 100% effective. His answer was that Traffic Scotland didn't want to close them!
So even when there's a simple solution to making the road safe, the authorities don't wish to act. Speeding wasn't what caused the deaths, but rather inaction by those responsible for a dangerous road.
As a side note, this area is covered by SPECs cameras, which covers all access roads around the town of Ayr. Unfortunately these cameras didn't prevent the policeman's death but, people avoid going shopping there now. So it actually hurts the retailers in Ayr!