Benefits of drafting.
Today I had a trip over to the south side of Edinburgh. Being a Sunday morning, the roads were reasonably quiet. I managed to get in behind a couple of HGVs at parts of my return journey (careful to keep a safe distance back), which helped push the air aside.
Here is the information for today's trip, as computed by my ScanGauge E: 65.1 mpg (UK) 54.2 mpg (US) 4.34 Litres/100km Max coolant temp: 84°C Distance travelled: 86.7 miles Maximum revs: 2957 rpm Max speed: 56 mph Average speed: 35 mph A nice Average mpg. Pretty pleased about that. |
IN the US roads have 13 stripes per 528 feet (.1 mile). I find that 3 stripes separation (close to stopping distance) at 70 MPH gives me about the same MPG as 55 MPH with no drafting opportunity. I prefer to drive the 55 MPH routes but sometimes there is a necessity to get there quickly. The Interstate here is 70 MPH going west, but the traffic is heavy almost always. There are spots where the average lane sees a car a second pass over the same spot (86,400 every 24 hours) on occasion. That's traffic density where it is very difficult to maintain even the speed limit.
|
A big truck, travelling at 56 mph makes a much bigger hole in the air than one travelling at 40 mph. I found that today, through the mandatory 40 zone on the new bridge.
We are advised to leave 2 seconds between vehicles (Only a fool breaks the two second rule). Goods vehicles, in Scotland, are restricted to 40 mph on single carriageways (two lane), 50 mph on dual carriageways and 60 mph on motorways. Trucks are fitted with speed limiters set to 56 mph. So if you sit in the lane the trucks are using there is no need to speed. Most trucks seem to sit on the limiter, when road and traffic allows, irrespective of the actual legal limit. |
At 70mph, including reaction time to a surprise event, I'd think 4 stripes would be more likely the minimum stopping distance. Three might work for 60mph. I usually follow at least 7 or 8 stripes back at 60mph or above. The little bit of fuel savings isn't worth the potential little bit of dead being close enough to benefit might entail. EEMMV
|
Drafting behind a truck to gain a few miles per gallon is throwing the dice for very little gain.
|
Quote:
|
Quote:
I have never had an accident where my distance behind the car in front of me was an issue. Try the DC beltway, or Atlanta, LA, Jacksonville Florida, New York City, Detroit or any other major metropolitan area. I pick the spot and lane so I have an escape route to the right, only on Interstates. The only through roads here are east to west or reverse. Stand next to the entrance of the Hampton Roads Bridge tunnel and count the car per second for one 86,400 second day. then preach to me how to drive in that traffic for 50 years without a single incident. I don't allow any outside distractions when I am in that driving scenario. Sure I prefer the less traveled routes, but at times it is not an option. Want more separation, go ahead, then look in your mirror and there is an 18 wheeler 20 feet from your rear bumper. It's called the corridor effect. |
Quote:
Another scenario -- also caught abundantly by dash-cams -- is the driver in front of you suddenly swerves to avoid an obstacle (like a stopped vehicle), and you (tailgater) have insufficient time to react, so you end up driving right into the obstacle. Again, it's highly undignified to participate in such easily avoidable, driver-induced collisions, whose risks are amply covered in Driver's Ed 101: See far enough ahead for your speed to be able to easily (1) Identify and assess risks, (2) plan an avoidance or mitigation strategy, (3) have the time to react when risk becomes hazard, (4) get your wits about you, and (5) execute your plan flawlessly. When you're tailgating a rig, you're flying blind and hoping for the best. I strongly recommend against that, regardless of you fuel economy benefits. I'm pretty sure the police would agree. |
It's drafting if you are a NASCAR or other racing driver. It's tailgating if you are on a public road. And it may work great for who knows how long but it's like the kid who eventually says "Yeah, but I didn't break my leg the first 834 times I jumped off the roof.".
|
Quote:
|
All times are GMT -8. The time now is 02:04 AM. |
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.