Do the police use TETRA while driving? Is hands free the answer? I observed a policewoman in a car using a TETRA handset, no external antenna (!). The MTHR (DfT) study, somewhat buried (pp. 87-99) concludes:

http://www.dft.gov.uk/stellent/groups/dft_rdsafety/documents/page/dft_rdsafety_033662.pdf (total 206 pages of other road safety things)

‘Driving performance clearly suffers when the driver is performing a simultaneous task. The results of most driving measures showed similar fall off in performance for each of the three driving conditions. However, there was an interesting and important difference in reaction time results that showed the worst performance scores in the hands-free condition. This result was complemented by the subjective workload scores that showed hands-free conversation rated higher than in-vehicle tasks or talking to a passenger. By looking at the conversation itself, we have shown a distinct difference between talking over the carphone and talking to a passenger. There is an important difference between communicating with a passenger who is directly involved in the concurrent drive, and with one that is remote and uninvolved.’

No direct link from the MTHR website to this. In fact the website is really out of date and useless for homing in on any of the direct research results.

Other driving/mobile links at http://www.tetrawatch.net/main/news.php

Andy