The Burnley tunnel has two speed cameras, one located approximately 430m from the entrance and the other located approximately 2,140m from the entrance. As I investigate speed cameras I often find interesting information I'd not considered.
I found this article which felt like there were a lot of frustrated drivers.
Why the hell do people go so slow in the Burnley tunnel?! : melbourne (reddit.com)
However, unexpectedly I found this article which goes a long way to explaining the issue.
Transurban's data efforts drive changes in motorist behaviour - News - IoT Hub
It appears people have no issue going down the hill at the speed limit but once the grade starts to go up people don't increase their speed quickly enough and that causes traffic to slow down behind them.
You can see two things are in play. The first is the slope of the road which initially goes down and then goes up. The second is people trying to keep within the speed limit because there's two speed cameras and very hefty fines waiting for those who infringe.
The slope of the road. If you check my driving speed along Foote Street/Reynolds Road you'll see that even though the speed limit is 70km/h and I try to drive near the speed limit, in fact as I go down the hills I have to brake and then accelerate to go back up the next hill and the driving speed can easily drop by around 10km/h.
Speed cameras. I don't know about others, but normally I drive with my speedometer showing that I'm driving near the posted speed limit. Often the needle is slightly below. That means I'm really driving about 2 km/h below the speed limit. But where there's a speed camera I slow down even further as I have no trust in the government's facilities. So perhaps I'll be driving now at 4km/h below the speed limit according to my speedometer. But legally all speedometers show a speed that is higher than my actual speed. My speedometer is out by around 4km/h. So when I drive where there's a speed camera I'll be driving around 8km/h below the speed limit.
When you add the upward gradient change at the bottom of the Burnley tunnel plus my desire to drive and not get booked, I'd slow down to possibly 18km/h below the speed limit and whilst some of this is by conscious choice, most of it isn't. That means every car behind me would need to slow down so they don't run up the back of my car and that could easily cause the speed to drop a little further.
As you can see, with a posted speed limit of 80km/h, this can easily result in people needing to slow down to around 60km/h to match the speed of the traffic.
So what people are getting frustrated about and calling Australians bad drivers, is really a lack of knowledge on their part as to how the car operates and how others drive. I really wish my car speedometer showed the exact speed and then I'd drive perhaps 2km/h below the speed limit for caution around speed cameras. The government has legislated so that doesn't happen so that's their fault. The angle of the slope in the Burnley tunnel is by design so again the government's fault. A much smoother curve could assist in smoothing out people's speed.
As to the paranoia with speed cameras that's because the government has legislated speed cameras can be out by up to 2 or 3 km/h (2 km/h is used in the Burnley Tunnel) for inaccuracy of their equipment. Now unfortunately if feels like the government gives themselves an error for margin but not us. Actually the government does give a margin for error but they do not publish that margin as they don't wish for that to become the default speed limit people start using.
As for relying on your cruise control to maintain the speed limit, if you haven't tested your cruise control you should think twice. My cruise control (an older Toyota Avensis) does not slow me down, but only keeps me at the speed. Thus when going down hill my car will exceed the speed limit. A Mitsubishi I tested keeps the car at the speed limit and slows down going down a hill, but when reaching the bottom of the slope can lose 15km/h as it adjusts to go up the next slope as in the Burnley Tunnel. Until I tested a number of cruise controls I would have thought cruise controls all kept you at the set speed and that's not been the case in my testing.
So to answer the question "why do people go so slow through the Burnley Tunnel" is not because they're not bad drivers. They're actually driving as people would expect them to. Slightly lower than the speed limit to ensure they look after their own financial interests, braking when they should on the downward slope to ensure they don't break the law and accelerating when the road starts to go up but unfortunately the upward slope slows the car before the person's acceleration returns the car to the desired speed. All cars following need to match (or usually go slightly slower) to ensure they keep a safe distance. There is nothing untoward going on. People aren't bad drivers. It's just the way cars and people work.
No comments:
Post a Comment