A TfL spokesman said that initially the system will merely alert drivers when they are entering a new speed limit area, but the design extends to the ability to slow vehicles automatically that exceed the limit.
Strongly opposed the concept are the London Assembly Conservatives, as well as the Safe Speed organisation. Conservative Assembly transport spokesman Roger Evans said: "This proposal is ill thought out, expensive and dangerous. We have real fears that accidents may result from vehicle engines cutting out during manoeuvres. Drivers must be able to trust their vehicles [to repond] at all times."
Meanwhile Safe Speed founder Paul Smith commented: "ISA is a fatally flawed technology for road safety. We need drivers engaged in the task of driving, adjusting their speed to suit immediate conditions.
"ISA will turn drivers into dangerous zombies trusting the satellite and the speed limit to control the vehicle for them. Clearly those who advocate this system understand nothing about the process of safe driving or road safety."
For more breaking car news and reviews, subscribe to Auto Express magazine. We'll give you 6 issues for £1 and a free gift!