Can you exceed the speed limit to pass?

When I took my driver’s license in exam in Massachusetts in 1970, one of the four questions I got wrong was, “is it OK to accelerate past the speed limit to pass another vehicle?” I said it was. I was wrong.

I like to think I was merely ahead of my time.

Rep.Tom Rukavina, who occasionally regales the House with stories of his driving experiences, has gotten initial approval of a bill that would allow Minnesota drivers to exceed the speed limit by 10 mph on roads where the speed limit is at least 55, when passing a vehicle going slower than the speed limit.

State Patrol Maj. Michele Tuchner expressed concern about drivers thinking they get the extra 10 mph when preparing to pass or after returning to the right lane, according to Session Daily.

  • http://imagespetites.blogspot.com kate

    GREAT idea. I hate passing people, but I love driving fast! Perfect

  • Betsy

    Does this pertain only to single lane highways? And who’s going to decide if you’re “passing” just by driving in the left hand lane? How about on metro freeways? After all, you’ll be passing someone almost the whole time you’re on a freeway. Laws like this are unenforceable and just plain dumb.

  • http://www.mnenergychallenge.org Neely
  • Matt

    People are already driving 60 to 65 mph in 55 mph zones, and still accelerate beyond that to pass cars that are speeding. We need to up the fines to encourage law enforcement to start enforcing the speed limit. Maybe that would help fix the states economy. Same goes for the stretches of interstate where the speed limit is 70 mph.

    Does anyone really need to exceed the speed limit unless it’s an emergency?

    If people are speeding because their late, suck it up and be late. Tardiness is no excuse to break the law.

  • Mr. Sanelane

    Neely says “Almost all vehicles are built to operate most efficiently at 55 miles per hour, which means that driving faster than 55 decreases the efficiency of our cars.”

    Does Neely honestly think car manufacturers around the world have all fine-tuned their engines to optimize fuel consumption at the USA’s former politically set speed limit of 55mph? That’s not how the laws of physics work, buddy.

    The most efficient car, from a greenhouse gasses point of view, is the one that is never started up.

    It’s all trade offs. Do we want to get some where in a reasonable amount of time, without the safety danger of boredom? There is nothing magical about 55mph.

    The greenhouse gasses emitted by modern automobiles is a lot smaller than other sources, e.g. coal fired power plants.

    Matt: how high do you think the fines would need to be to reach your “utopia” of everybody driving exactly the speed limit? They’re already in the $200 to $300 range for the average highway speeder. Ever been unfairly victimized by a speed trap or a lying police officer? Or, conversely, ever called the police and had them not show up soon enough? Having them spend more time handing out speeding tickets is likely mostly counterproductive. We need photo-radar like they use in Europe, really.

  • Brian

    A law that is impossible to enforce or difficult to even determine (were you passing, were you going 12 miles over while you were passing?) is not really a law, is it?

    Another waste of time and taxpayer’s money, although I’m pretty sure I answered the driver’s test question the same way as Mr. Collins!

  • Bob Collins

    I drove home from Moorhead early this morning at 70 mph. I got 31 miles to the gallon and by my calculation my car’s engine was running more than an hour less than had I gone 55.

    I’d be interested in figuring out who would be “greener” in that situation.

  • CJ

    Bad idea!

  • http://imagespetites.blogspot.com kate

    Ooh, good question Bob. Too late for me to figure it out though…

  • Bpb

    Collins, I assume you meant that Rukavina’s bill would make it O.K. for people to exceed the speed limit by 10 mph only when they are passing vehicles going under the speed limit. If that’s the case, his bill would only make it legal to do what safe passing (if there is such a thing) usually requires.

    In other words, if you could only go the speed limit when passing another vehicle, there would be few times when it would actually be safe to pass, because the passer would be hanging out in the oncoming lane way too long.

  • Bob Collins

    Correct. The bill assumes the person you’re passing is go slower than 55.

    It would be interesting to consider whether your premie is correct, however. In fact, it’d make a great questions for the new math grad standards.

    i.e. “If you’re overtaking a vehicle traveling 50 mph, how much longer would it take you to pass the vehicle if you were to overtake it at 65 mph instead of 55 mph.”

    Anyone?

  • Bob Collins

    Well, you knew I couldn’t go to bed until I figured this out, right?

    Here’s what I’ve come up with.

    At 65 mph, you’re traveling 95.3 feet per second

    At 55 mph, you’re traveling 88 feet per second

    At 50 mph, you’re traveling 80.6 feet per second

    So a car passing a vehicle that’s traveling at 50, gains 7.4 feet per second. Figuring a car is 15 feet long, add another 20 feet in each direction for a safe transfer from lane to lane, that would mean it would take 7.4 seconds to pass if he/she is doing 55 mph.

    A car passing a vehicle that’s traveling at 50, gains 14.7 feet per second if he/she is doing 65. That would be 3.7 seconds.

    So apparently, for every 10 mph over the speed limit, you halve the time it takes to pass. But the difference between 55 and 65 is 3.7 seconds.

    Someone better check that math.

    Oh, and of course this doesn’t factor in that the person you’re trying to pass probably speeds up a little bit as soon as you start to pass. Man, I hate that.

  • Bob

    Impressive late-night math, but factor this into it:

    Decent driver training tells us that it is not safe for the passing vehicle to move back into the lane until the passer can see the entire front of the passed vehicle in their rearview mirror. That’s a lot more than 20 feet; I’m guessing it’s more like 35 or 40 feet. But it makes the point that it is even more critical to be going faster when you overtake someone, as you need additional time to establish a safe “dropping back in” distance.

    And in the event that a person speeds up when we’re trying to pass them, such that we are seriously maimed or killed, our estate would have a strong criminal vehicular operation claim. ; )

  • Nate

    I definitely passed a MN Trooper last fall because I was in the left lane and felt that it was important that I avoid breaking the law for sitting in the left lane.

    Once I slowed down and pulled to the right lane she pulled me over. The officer did not like my excuse that speeding up was OK to pass and now I see why.

  • http://rrchapman.us Bob Chapman

    In Washington State, it IS legal to exceed the speed limit by any amount while passing on a two-lane highway. It is also illegal in Washington State to delay 5 or more vehicles when on a two-lane road, also (you pull onto the shoulder at next safe spot to let others pass). Also, the WashDOT labels specific shoulders when safe for daytime slow vehicle use (use like a truck lane).

    The shoulder driving and no speed limit when passing does NOT apply when there are two traffic lanes going in the same direction. This means you can’t do it on I-90 or other Interstates, or where there is a truck lane.

    We do have mountains out here, though. While WashDOT has many truck (slow vehicle) lanes on roads like US 2 and US 12, they aren’t everywhere. Did you ever get caught behind a logging truck?

    Other oddities include having permitted left turn on red when turning onto a one way street and the 18-inch (or more) painted barrier lines on streets (treat like median).

    When moving here, taking the written test had elements of learning to drive all over again. They even ask a motorcycle question or two on the automobile written test. It’s in the driver manual published by the Washington State Department of Licensing.

    What’s a measly 10 mi/hr when passing. Meh!

  • Bismuth

    I drove home from Moorhead early this morning at 70 mph. I got 31 miles to the gallon and by my calculation my car’s engine was running more than an hour less than had I gone 55.

    I’d be interested in figuring out who would be “greener” in that situation.

    That’s easy; just compare your MPG. Whichever is higher used less gasoline for the trip, regardless of time spent driving.

  • http://rrchapman.us Bob Chapman

    Doing the math (I am going to use 60 mi/hr as the speed limit, as it is on most 2-lane rural Washington State roads):

    70 mi/hr is 102.7 ft/s

    60 mi/hr is 88 ft/s (not 55 mi/hr)

    50 mi/hr is 73.3 ft/s

    You need to leave 2 seconds (minimum) for safety behind the car in front of you. Likewise, you should be 2 seconds in front of the car you overtake. So you need to start passing 176 ft behind another vehicle, and not pull in (in theory) until you are 176 ft in front of it. That is 352 ft total.

    Let’s say you, in Car 1, is doing 60 mi/hr; Car 2 is doing 50 mi/hr.

    D1= D2 + 176 ft (+ length of C2 if you really want to do it right, but will leave out for this example)

    D1 = 88 ft/s * t

    D2 = 73.3 ft/s * t

    This means

    88 ft/s * t = 73.3 ft/s * t + 352 ft

    14.7 ft/s * t = 352 ft

    t = 24 s

    You are passing for about 24 seconds if you don’t go over 60 mi/hr.

    Let’s do this for Car 1 doing 70 mi/hr, which is reasonable for most cars, and definitely reasonable for my motorcycle.

    (Still using 352 ft for before and after. In reality this number is wrong even for 60 mi/hr because it doesn’t take vehicle length into account. Besides, there is the time it takes Car 1 to speed up from 50 mi/hr when starting to pass. We are just approximating here.)

    102.7 ft/s * t = 73.3 ft/s * t + 352 ft

    29.4 ft/s * t = 176 ft

    t = 12 s

    So, by going 10 mi/hr over the speed limit, you will cut the time to pass in about half.

    I would have needed to use calculus to bring this number in closer. I don’t think you are going to solve differential equations while driving, so I gave you this approximation to give you a very rough idea of how this works.

    On any two-lane highway (mountains or prairie), I would say that only exposing yourself to oncoming traffic for about 12 s is better than 24 s.

    Or, most of us do take about 10-12 seconds to pass another vehicle on a two lane road. Most of us would get nervous at taking 24 seconds, so we will cut something short–which is dangerous. This means that, assuming you have 10-15 seconds of clear, straight road (you don’t pass on turns, do you?), passing will possibly be safer with allowing exceeding the speed limit.

  • Bob Collins

    Props to you, Bob. That’s some serious math work.

    One proposal I came up with while driving 1,390.5 miles (and back) a few weeks ago is one that would prohibit two semis from occupying adjoining lanes for more than 24 seconds.

  • Dennis Whicher

    It definitely is safer to speed while passing in an oncoming traffic lane. So long as your speed is reasonable and prudent, every second you save in the oncoming lane is a second you do not have to worry about a head on collision. And you can get far enough ahead of the car you are trying to pass to avoid hitting (or being hit by) it.

    This is truer if the car you are trying to pass does speed up. Assuming it is straight ahead, if you are allowed to speed up to 80 or 85 MPH to pass, there is a pretty good chance of making it safely, and they are not going to be able to speed up enough to prevent safe passing. On the other hand, if you are only allowed to do the speed limit, you are exposed to oncoming traffic longer–and, if the other car speeds up, it might prevent safe passing.

    Note that this argument is only valid when passing requires going into an oncoming lane, and when it is safe to do so at all. There is no excuse to pass on curves or where you cannot see the oncoming lane clearly. Also, you need good judgment if there are many cars, not just one, ahead of you. And one should not be excused to speed beyond a reasonable and prudent speed.

    On highways where you can pass without entering oncoming traffic lanes, I believe that the speed limit should already be “reasonable and prudent”. Slower traffic should keep right, and faster traffic should only stay in the left lane until the pass is safely completed. This policy would reduce traffic tie-ups and backups to a minimum, while allowing people to drive at the fastest reasonable and safe speed they can. At the same time, in very bad conditions, the “The speed limit posted was 55″ would not hold up–if you cannot stop in the distance you can see ahead of you, you are not driving a safe, reasonable, and prudent speed.

  • dustin

    pawlenty passed this provision. you can exceed 10 mph over the speed limit if its 55 or greater on 2 way highways. this does not mean you can exceed over the speed limit when passing a vehicle on a 2 lane same direction road. for example you CAN NOT exceed the speed limit passing a vehicle on 35w,35e,169,494,694,ect. you also can NOT exceed the speed limit by 10 mph to pass a vehicle on a road in which the speed limit is less then 55 mph.

  • wayne

    i was looking for something on the enforcing of speed limits relative to the placement of speed limit signs, stumbled into this…i would suggest that we examine the real goal of passing first, and then instead of calculating how long it takes to pass, calculate the benefit of passing relative to the goal….in general, i think everyone would agree that the goal of passing is to minimize the time it takes you to get from point A to point B (i seriously doubt anyhone thinks about passing as just something fun to do). Let’s look at a typical example. Let’s say that Point A to Point B is 60 miles. Here’s Scenario 1: Let’s ignore accleration and decelartion, and let’s assume you’re driving the speed limit of 60 miles an hour, and that you manage to maintain this speed for the entire duration of your trip. So, at 60mph, it will take you precisely one hour, or 3600 seconds, to get from point A to point B. Now, here’s scenario 2: Everything the same as Scenario 1, but once during the trip at exaclty the halfway point you come upon someone doing 55mph. You slow down to 55 mph for 1 minute, then accelerate to 65 mph to pass for about 20 seconds (using approximations to the above approximations), then return to 60 mph (don’t want to get a speeding ticket!). Someone check my math, but I get 3604 seconds. Then, Scenario 3, the same as Scenario 2 except I don’t pass, just stay at 55 the whole rest of the trip. That get’s me to B in 3764 seconds. SO….executing the pass got me to point B 160 seconds quicker than not executing the pass….so, you tell me…does getting there 160 seconds (2 minutes 40 seconds) sooner on a ~1 hour trip (that would be a 4% reduction) justify passing at all? what one should really do is determine the minimum speed you’re willing to not pass at (just how many seconds really matter to you?). On a 1 hour trip, I’m thinking maybe 10 minutes is the maximum you should be willing to be delayed. This minimum speed though is a function of when you encounter the slow moving vehicle. The later in the trip you encounter the vehicle, the slower it can be moving before you have to pass to not exceed your 70 minute goal. But let’s say you encounter it at the 30 minute mark. In that case, if the vehicle is going at least 45mph, don’t bother passing.

    What would be really cool is to have all of this displayed on the dashboard. At the beginning of the trip you enter the maximum amount of dealy time, and the computer calculates whether or not you should pass based on the car’s built in radar that determines the speed of the vehicle in front of you. If you should pass, the voice says “pass”.

  • Andrew Jackson-Harrison

    This is kinda funny cause it states that you are allowed to speed to pass another moving vehicle as long as its widosnt exceed 10mph over the speed limet. I had passed another vehicle then pulled over to the side of the road so i could piss in an empty container and when i stood up thats when i sawthe officer in my mirror. So i sat back down te he opened my passenger side door. I had to excuse the officer so i could do what it was i pulled over to do in the first place. The officer is in northern CA and his name is Manning and ID# is 18660 just incase he does it to you…

  • Andrew Jackson-Harrison

    This is kinda funny cause it states that you are allowed to speed to pass another moving vehicle as long as its widosnt exceed 10mph over the speed limet. I had passed another vehicle then pulled over to the side of the road so i could piss in an empty container and when i stood up thats when i sawthe officer in my mirror. So i sat back down te he opened my passenger side door. I had to excuse the officer so i could do what it was i pulled over to do in the first place. The officer is in northern CA and his name is Manning and ID# is 18660 just incase he does it to you…