As per the summary at http://www.mit.edu/~jfc/laws.html, Texas is one of the three states where there are no absolute speed limits -- a speed in excess of a posted limit is prima facie evidence that the speed is not reasonable and prudent and that the speed is unlawful (Texas Sec. 545.352).

So, what if you were going with the flow of the traffic? Is that a valid defense that you were driving at a reasonable speed?

What if you mentioned to the officer once stopped that you were simply going with the flow of the traffic, and he didn't really seem to object?

What if the speed limit was 70, the flow of the traffic in your lane was 75 to 80, the citation received was listed for 80, but the officer claims that he has gotten you on his radar at 85? Could it be argued that in such instance the actual speed limit was supposed to have been at least 75 (as per the 85th percentile speed), and thus going 80 (as per the ticket) is less than the 10 miles over the limit, which is what the minimum charge an officer claimed he could give a citation for? Would this be a valid defense in Texas, overthrowing the citation?

  • @feetwet, why did you remove the prima-facie-speed-limits tag? if someone lives in one of the states where prima facie speed limits exist, how are they supposed to browse all questions on the topic?
    – cnst
    Commented Aug 27, 2015 at 18:25
  • We don't even have a "speeding" tag, or anything more specific than "traffic." I.e., "prima-facie-speed-limits" would be two levels more detailed than existing tags. Not to say we can't create it: if you think it would be helpful suggest it in Meta and let's get a good tag schema for this subject, or at least some agreement that this wouldn't constitute excessive tag proliferation.
    – feetwet
    Commented Aug 27, 2015 at 18:39
  • 1
    @feetwet, I'm not sure i see your point -- the site is new, so, not that many tags are present; traffic already means speeding, but the prima-facie limit states are somewhat rare, so, they deserve to be identified as such, imho. not sure what i'd ask for in meta -- perhaps you should create a discussion if you want the tag removed? there wasn't a prima-facie tag, either, but that's not an excuse to not have one!
    – cnst
    Commented Aug 27, 2015 at 18:44
  • Fair enough: meta.law.stackexchange.com/q/247/10 is the meta discussion. You can roll-back my edit in the meantime (and earn a badge in the process!).
    – feetwet
    Commented Aug 27, 2015 at 18:54

3 Answers 3


Texas and California are actually what are called Presumed Speeding states, unlike most others which are Absolute Speeding states. (There is a little known third category called Basic, but this is uncommon). In a presumed speeding state, a speed-limit violation offers someone in your shoes far more flexibility in building your defense than the more common absolute state.

In states that use this presumed system, such as California and Texas, it is not illegal to drive over the posted limit as long as you are driving safely and this can be established. For example, if you are driving 50 mph in a 40-mph zone, you are "presumed" to be speeding, yes. However, despite this prima facie evidence (meaning "on its face") of speed in excess of the posted limit, if you can show you were driving safely you may be able to mount a pretty decent defense. Just because you got a ticket is not prima facie evidence beyond a reasonable doubt that you were speeding. You are presumed innocent. If they prove you were speeding this is all they need to make their case, unless you rebut it. But there is a lot of room to rebut this presumption – and that is if they prove it. They must (as with all criminal cases) prove you did what you are accused of beyond a reasonable doubt – the highest standard of proof in the U.S.

So, if everyone was going 80 MPH in a 70MPH zone, you would argue that the road was (I'm assuming) dry, unmarred, you were traveling in heavy enough traffic that to slow your speed to the posted limit would actually be less safe than traveling with the flow of traffic. You can talk about the state of your vehicle (repair, handling, etc.), how you stayed in one lane, and you can describe your skill at driving – especially if you have no other tickets and you have been driving for a long time.

If you were weaving in and out of traffic, riding someone's bumper, if it was pouring rain, the road was bumpy or under construction, or if you admitted speeding (if you did this you can still rebut with a showing of safe driving, but ignore all info regarding challenging radar or other means of determining speed), or if any other evidence exists that the officer would testify to that shows you were not driving safely, this will not be successful. A successful example of a speeding defense in Texas: on a clear, dry morning with no other cars on a wide, straight road, a man is pulled over for being clocked going 50 mph in a 40 MPH zone. He had a perfect record and had been driving 22 years. He was driving a 2-year-old car. He convinced a judge that this was driving safely given those conditions and was acquitted. That's because facts presented were sufficient to "rebut the presumption" that by going over the posted limit he was driving at an unsafe speed.

NOTE: Never bring up your driving record unless it is spotless. Unless you are a habitual offender it cannot be used against you or be brought into evidence at all, unless you open the door.

You can also mount a defense based on the radar detection device, if one was used. You can seek records as to when the calibration fork was last checked, when the last time it was professionally calibrated (rather than self calibrated). You can ask, in a leading way (only if you know) how close the car behind and in front of you were (you don't want to be too close to the car in front of you, however if the cars were tightly grouped it is more likely the radar detector could have read another vehicle): e.g., "Isn't it true that the car behind me was only 1.5 car lengths behind me?" Only do this if you know, but if you can get the officer to admit that the car behind you was close, that can be used to rebut the radar detection and goes to the argument that driving slower would have been dangerous and you were driving safely with the flow of traffic.

You should be prepared to put on an entire trial if you fight the ticket. In Texas, I believe speeding is considered a Class C criminal offense (rather than a civil offense as in most absolute states); hence, they have to build the prima facie case against you and prove it beyond reasonable doubt. If you can afford one, get a good traffic violation attorney. Always choose a jury in this type of case. Everyone speeds a little and you are far more likely to be acquitted by a jury than a judge. You should also ask to have the case assigned to the county seat; request this in writing ASAP.

If you are trying the case, be prepared to go after the officer. Note any distinguishing marks on your car (if any), recall what you wore, what time of day, the lighting, all that. Even go back to the scene at the same day and time and take video showing the flow of traffic, (hopefully) the straightness of the road, etc. Cross-examine him on all facts with confidence and in a leading manner. Always ask for the calibration reports and you will get all evidence against you in discovery.

This thing about 10mph being the minimum they can give a ticket for: ignore that, it's rubbish! It's meant to get you to admit to him that "you were only going 8 or 9 over." Also, that whole percentile argument is not relevant and will not work at all. You must show that you were driving safely given all the facts and circumstances to rebut the presumption that you were driving unsafely by speeding.

It is worth fighting as you will also incur surcharges, increased insurance rates, and points on your license that are cumulative and stay for 3 years – a certain amount of which gets you suspended if you get (or have) more violations.

  • 1
    Great answer, thanks. However, I believe you're incorrect about California -- as per the linked page, only limits of 60 mph and below are prima facia limits, the 65 (and 70) limits in Cali are absolute. Also, the thing about Texas is that they offer a reduced fine and clean record if you select a driver education course prior to appearance, so, following your advice of hiring an attorney and doing the whole trial with the jury seems a bit impractical in such light.
    – cnst
    Commented Aug 27, 2015 at 4:15
  • My Pleasure. Unless California has changed in the last year, what I mean about is that not all are absolute and is some ways can be compared to Texas, in that you can show safe condition as a defense at some speeds. THere are other substantial differences but it is noted in a professional publication as a Presumption state.
    – gracey209
    Commented Aug 27, 2015 at 4:26
  • professional publication making a mistake?! now, we all know that NEVER happens! :-) which one is it? nolo webpage is quite explicit that only certain speeds are that way (sadly, they then group Texas and California as if both are same), and if you look at the laws from the link referenced from MIT, Cal Sec 22357 says, prima facie speed limit of 30, 35, 40, 45, 50, 55, or 60 miles per hour or a maximum speed limit of 65 miles per hour, so, clearly, California is indeed likely Mixed, as per MIT summary.
    – cnst
    Commented Aug 27, 2015 at 4:49
  • ATLA journal "On the other hand “presumed” violations of the speed laws pertain to a possible violation of California Vehicle Code 22350. If the posted speed limit on a city street is 40 miles per hour, that is a “presumption” that it is not safe to go faster than 40 miles per hour. However, you can raise a defense that you were going 45 miles per hour at 3am and there was no traffic on the street. In that instance you could win your case with that defense."
    – gracey209
    Commented Aug 27, 2015 at 4:53
  • I'm searching some professional databases and this is still presumed to be the case although CVC Ch.n23350 is, in some legal circles, being called a non-starter in current judicial climates as new statutory frameworks are creating absolute limits in a huge variety of roadways, stating maximums for posted and for non-posters, So, California could becoming arguably an absolute state except in the rarest of circumstances.
    – gracey209
    Commented Aug 27, 2015 at 5:01

You seem to misunderstand what prima facie means: accepted as correct until proved otherwise.

The facts are that you exceeded the posted speed limit; therefore it is legally accepted that you were driving at a speed "greater than is reasonable and prudent under the circumstances then existing".

To overturn the prima facie assumption you must prove beyond reasonable doubt that the speed at which you were travelling was "reasonable and prudent under the circumstances then existing". Demonstrating that other people were also driving at this speed does not show that you were "reasonable and prudent" because prima facie they were themselves not "reasonable and prudent".

A possible (if unlikely to succeed) defence would be to demonstrate that the combination of your driving skill, your vehicle's performance and the road conditions were such that you were as or more capable of avoiding a collision at 80mph as the general population is at 70mph. A professional race car driver in a high performance vehicle on a perfect driving day might have a chance with this.

  • 1
    To overturn a prima facie assumption of a crime isn't the standard that you have to merely cast reasonable doubt on the evidence? Proving one's innocence beyond a reasonable doubt ... actually, it would be an interesting question when that has to be done; but I don't think this is one of those situations!
    – feetwet
    Commented Aug 27, 2015 at 18:47
  • I think with prima facie evidence the point is that you can reverse the situation: Drive 45 in a 40 and it is assumed that you were dangerous unless you can prove otherwise. You can then give evidence that proves it was likely not dangerous - now that state has to prove you were driving dangerously.
    – gnasher729
    Commented Aug 30, 2015 at 15:36
  • I've gotten a not guilty verdict in Texas and a hung jury in another case in Texas using this exact defense. It's not that hard here for some juries.
    – mark b
    Commented Jun 17, 2019 at 19:20

If you driving faster than the speed limit you are not necessarily traveling faster than the reasonsonable and prudent speed. Many hiways have had traffic surveys done on them to determine the 85 th percentile or ( reasonable and prudent speed). This speed is in many cases , if not most cases hhigh or much higher than the posted speed limit. Also these surveys are done with an already posted speed limit on these roads , therefore the actual reasonable and prudent speed, the 85th % is even higher because many drivers are simply obeying the posted speed limit to defend themselves from traffic enforcement rather than driving as fast as is reasonable and prudent.

  • This doesn't really answer the OP's question, "is driving at the speed of the other traffic a defense to a charge of excessive speed?" Please indicate whether and if possible how driving at the speed of other traffic is a defense or is evidence helping to establish a defense. Please cite sources if possible. Commented Jan 21, 2019 at 23:39

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