Have your say: 80mph speed limit for motorways and 20mph for residential roads?

This is my local london

How fast do you think people should be allowed to drive on motorways and in built-up areas, and how best can speed limits be enforced?

Last month plans to raise the motorway speed limit from 70mph to 80mph appeared to get kicked to the kerb by transport secretary Patrick McLoughlin.

In 2011 when the possible move was first announced previous transport secretary Philip Hammond said the 70mph limit had resulted in millions of motorists routinely breaking the law. He claimed a rise to 80mph would "restore the legitimacy'' of the system and benefit the economy by ''hundreds of millions of pounds''.

However, last year campaign groups estimated raising the motorway speed limit to 80mph would cost society an extra £1 billion a year, including £766 million in fuel bills and more than £62 million in health costs. It was also predicted the higher limit would lead to 25 extra deaths and 100 serious injuries a year.

Meanwhile, the question of what speed restrictions should be applied to areas such as residential roads, town centres or near schools is often a thorny issue.

Some claim lower limits such as 20mph in built-up areas improve safety while others says they lead to longer travel times as well as increased congestion and pollution.

What do you think the motorway speed limit should be? Would increasing it make a big difference to how people drive?

Are you in favour of lowering speed limits in residential areas? What other traffic calming measures work well?

► As with any rules, speed limits are meaningless without proper enforcement and deterrents, so what are the best ways to make sure people stay within the law?