As a neutral, in the discussion about safety, I find the evidence presented AlterEgo to be definitive and if I was an Inspector at an Inquiry (I have attended many road scheme Inquiries) I would be more convinced by his evidence than the other contributions. When one takes part in these things, one has to accept whatever methodology has been laid down by the responsible authority, and the statistics that that authority is prepared to accept.
Try any other angle; it may be an interesting slant on the data or other data which one prefers to be used, but one will be ignored and deserve to be ignored.
An example on safety is the following (from memory but it demonstrates the point). These data are expressed as number of collisions per million vehicle-kms travelled*. If the proposal covers 10 km and a million vehicles pass through per year, the annual veh-kms is 10 million. The collision rate, broken down into fatal, serious and slight injuries, will be expressed as a ratio to that total travel. Note that non personal injury collisions are ignored by the police. If, because you had an airbag and were wearing a seat belt, you emerged from the wreck without a scratch, there would be no collision record created by the police, for the statistics.
Now the trick. If the number of personal injury collisions rose on the stretch where the new scheme is to be built,, bypassing the old, was to rise on a yearly basis and there were 10 fatals and now there will be 20, one would think that in this respect at least, building the bypass would not be a great idea. However, if by building the bypass, a bottleneck is relieved (say 5 minutes**) and traffic doubles, the Inquiry will conclude that the new road is as safe as the old because the ratio stays the same.
So the scheme above leaves 10 more families in grief - every year - but try arguing that at the Inquiry, and that these deaths are the appalling price of relieving the current delays. Try arguing that people should accept the delays and not accept the deaths.
Guess what, you will be ignored by the Inquiry report to the SoS.
* It may be differently expressed nowadays, but it does not change the thrust of my example.
** you would be surprised how little time is lost by seemingly long delays, intensely frustrating those are of course, if you are in the daily rush hour queue. "Just put the radio on and relax" would be our friend the environmentalist's argument, or better still, go by train, it's almost infinitely safer, (even if DOO!), and use the internet.