By Tim Foster
To assist in their traffic policing duties the British and French Police had the shared use of a radar speed gun, the accuracy of which had to be checked and certified from time to time. This task fell to the PWD, specifically yours truly, and had to be witnessed by representatives from both police forces.
The method used was to drive a vehicle at a constant speed over an accurately measured distance, note the time taken and calculate the true speed. At the same time the vehicle’s speed was checked using the radar gun. Several runs were undertaken at different constant speeds and the timed results and gun results compared.
To carry out the checks a long, straight stretch of level asphalt was needed with little or no traffic so we used the runway at Bauer Field. At some time someone had set out the measured distance – 200 metres I seem to recall – and marked it using metal pins driven flush into the asphalt at the edge of the runway.
On the appointed day, after getting clearance from Civil Aviation and Air Traffic Control, who assured me there were no flights due in or out for some hours, I met the representatives of both police forces on the runway. The French Police sent a couple of lowly gendarmes, who were to assist me with the timing but the British sent Inspector George Kalsakau, who had the speed gun, and a Sergeant (David I think) who was to drive a police car over the measured distance.
It didn’t take long to find the measured marks and we set about our project. We agreed that the checks would be carried out at 30, 40, 50, 60 and 70 km/h with two runs at each speed. I would time the runs with the help of the gendarmes and Insp. Kalsakau would measure the speeds with the gun. I think any attempt to relieve the Inspector of the gun would have met with stiff resistance.
We were well on with the job, Sergeant David had been merrily whizzing up and down, when we were interrupted by a loud hailer from the Control Tower exhorting us to clear the runway. Looking up we saw the lights of a twin engined plane on final approach about 500 metres away so it was a case of scampering as fast as possible to the Northern fence. The plane was a SOLAIR (Solomon Islands Airways) twin engined Piper. I later wondered what the pilot must have thought seeing us on the runway but I suppose it was something he was used to, flying in and out of bush airstrips.
When we finished our checks I was mildly surprised to find that at every speed, Insp. Kalsakau recorded exactly 30, 40 …etc km/h, whereas my timed runs, as to be expected, varied slightly from the target speed. The differences between timed and target speeds were quite small and I would also have expected the gun to pick up some variation from the target speeds but who was I to question Insp. Kalsakau’s competence so I signed off the gun as accurate.
Back at the office, I trawled the files for details of previous checks and was a little perturbed to find that my predecessor, who carried out the check before me, had gone to the trouble of assessing what errors would be incurred if the stopwatch we used was in any way inaccurate compared to an atomic clock!
I don’t know if anyone was subsequently prosecuted for speeding on the evidence of the gun; if so and if I had been called to confirm its accuracy I would have had an uncomfortable time. I’m afraid I would probably have passed the buck to George Kalsakau.
Copyright Tim Foster 2018 All rights reserved