Handheld speedcameras

Past two days there have been police officers at their favourite road ‘The mall’
but they werent at their usual location after the lights of Malbourough rd (heading East) but at the corner of Constitution Hill and The Mall

They were also pointing the speedgun towards Constitution Hill checking out people that were coming down.

Now i may be wrong but i thought that the speedgun works head-on! :ermm: if they are at an angle how can they get an accurate measurment of speed?

the red line is the direction i was travelling and blue line is the direction that the speedgun was pointed at