It would be likely to save MORE lives by posting the safest possible speed limits. Limits set at the 85th percentile speed of free flowing traffic under good conditions almost always result in the safest and smoothest traffic flow with the fewest accidents. On average, this will set most speed limits 10 mph higher than currently and safety will improve.
Britain used 85th percentile methods until about 20 years ago when under posted limits plus speed cameras and the millions of pounds of revenue to be raised took precedence over safety. Money trumped safety.
See the website of the Association of British Drivers www.abd.org.uk and our website for more information. James C. Walker, National Motorists Association, www.motorists.org, Ann Arbor, Michigan USA (frequent visitor to the UK to see family in West Yorkshire)