What's so attractive about LED as a replacement for the much maligned bulb unit? Other benefits aside, its shockproof. So, the real bottom line nugget is that its 'fit and forget' the end of what for most operators manifests itself as a steady stream of vehicles visiting the workshop for yet another bulb change and all the costs that go with it.

Britax say that their LED units are guaranteed for up to 100,000 hours of operation. Some in the know claim that in many cases LED longevity will match that of the vehicle they are fitted to. Steadily growing experience spread over five years suggests they might well be right.

Other pluses for LED lighting includes the low power draw - about 5% of that for the bulb it replaces, the opportunity to fit lower capacity batteries/alternators and/or the opportunity to fit more electrical equipment without the need to uprate batteries/alternators or run the risk of a flat battery.

On the safety front, LED carries a high intensity tag, ie it's a brighter light that can be seen from a greater distance - even in daylight. Some will also tell you that an LED brake light fires up that split second faster than its bulb equivalent - perhaps by enough to make the difference between a rear end shunt and a life changing close shave!

Stewart Dodd, workshop team leader at the Dundee City Council Waste Management Department can claim to be an LED pioneer. He started by retrofitting LED side markers on a hook lifter some four years ago, a move that stopped a daily visit to the workshop for replacement bulbs dead in its tracks.

Suffice to say that the first of four new refuse collection vehicles is due out of the MTH Falkirk workshops with all rear lighting converted to LED to match the side and front markers that came with the vehicle ex-factory.

Stewart awaits the day that vehicle builders wake up to the operating benefits of fitting LED as original equipment (OE) across the board. He has already told Dennis, but in the meantime, he is happy in the knowledge that the initial cost of retrofit to Dundee City Council is more than covered by an at least tenfold saving in the cost of replacement bulbs and the downtime it involves. And when you run a fleet of 150 vehicles, that's a saving the council tax payers in Dundee will surely savour!

Its been so long since he last had to replace a failed side marker or rear light on his vehicles that Alan Guild, the managing director of Falkirk Car Carriers, is hard pushed to remember just how many bulbs his 16 strong rigid and trailer fleet used to burn up each week. It was around 10 or 20, he reckons. Since switching to LED, fitted by MTH, lighting is no longer a problem,' he adds.

John Harrower, chief engineer for First Glasgow buses, has also recognised the operating benefits of retrofitting LED, not least in the reduction in unplanned downtime, and obviating the risk of attracting a prohibition thanks to a blown bulb.

Of the 900 buses in his care, the latest 300 to join the fleet, have already been so fitted ex factory.

Of the remainder, 400 are less than seven years old and work is already under way to get them all converted to LED lighting at the rear either as part of the on-going vehicle refurb programme or when a bus needs accident damage repairs. The LED units are a straight swap for the existing lamp unit.

Operators who have already seen the light, LED wise, are left scratching their heads as to why overall acceptance and adoption is taking so long and why they still need to resort to retrofit to get the spec they want. It appears to be one of those price/volume conundrums.

Speak to the marketing gurus at Britax and they will tell you that a sea change is in prospect. LED prices have stabilised as demand has ramped.

So, while no one might be prepared to hazard a guess as to when LED will replace the humble bulb across the board, the day will come when LED lighting, including for headlamps, will be OE for all vehicles be they wheeled or tracked, small or large, on or off road!