Discrete traffic sensor

We have a traffic safety problem where we live, which is simply that the exit from our house emerges onto an ‘A’ road where the traffic rushes past at around 50mph if they keep to the speed limit. What makes it really dangerous is that we live on a bend in the road and its impossible to see around the bend to see if any traffic is coming. If we emerge into the road at the wrong time, we have less than a second to get across the road and out of the way prior to any impact. Or alternatively we travel in the same direction as the traffic and risk a rear end collision.

So I decided to try and make a traffic sensor to warn us of oncoming traffic and today I finished it and I have to say I’m rather pleased with it!

Having had this problem for some years, and having had some dangerous near misses, we originally decided to buy one of those convex traffic mirrors you see around. Unfortunately, however we positioned the thing, we didn’t see traffic in the mirror until we saw it for real! Things came to a head when we got a letter from the council asking if we still had a lorry business on our property. (It used to be a lorry repair business and the council had put up signs saying “Lorries turning 100 yds”) They wanted to remove the signs “to reduce the roadside clutter”. I wrote back saying that there was no longer a lorry business but we urgently needed to have a meeting to discuss ways of making the road joining less dangerous. I requested they change the ‘Lorry turning’ sign with a ‘Concealed Entrance ahead’ sign. In fact the road has now moved up to second place in the league table of most dangerous roads in the UK.  It is the A5012 between Pikehall and Cromford and has jumped 4 places in 1 year! Anyway, so worried and concerned was the council that they didn’t even bother to reply to my letter! I started researching some kind of discrete warning device, as clearly the council were not going to dig up the road to insert one one of their “under the road” inductive loops.  I started by looking at radar but found it a bit on the  expensive side (£300+ just for the module). After doing some research,  I thought I’d see if an ultrasound sensor would work for recognising passing traffic (a bit cheaper at £15!). To cut a long story short, it does work, I’m pleased to say. You can read how its made in detail here. So what now happens is that the traffic passes the ultrasound sensor which I’ve cobbled together in an mdf housing (see top picture) and this detects the vehicle(s) passing and switches on a light 175 yds further down the road, which is where our drive emerges. The light is made of several high intensity LEDs and stays on for around 6 seconds which is about how long it takes for the traffic to reach the ‘collision’ point!