"IF the driver is suspected of driving while drunk, he is therefore suspected of a crime - he should be held down and a blood sample forcibly taken, consent or not."
This will lead to terrible abuses and violent confrontations.
Add a clause in bold type to whatever one signs when getting a DL, stating that when asked one will take a breathalyzer test, and that refusal to do so will be deemed an admission of drunk driving.
Don't sign, no license.