Here is a diagram of a section of road I drive on to work (traveling top-to-bottom)

enter image description here

The last sign on my way out of town (shown in the top left of the picture) says "SPEED LIMIT 45". A couple of miles later, there are two signs on my left (facing the oncoming traffic). If I turn my head I can see the "REDUCE SPEED AHEAD" and "SPEED LIMIT 45" signs.

That indicates that people coming into town must slow down to 45. No surprise there - they were traveling for miles on this rural road at 55 MPH and now need to reduce speed entering town. So that's an indication that at some point I can speed up to 55 driving away from town.

But when does that happen? There are no "SPEED LIMIT 55" signs in my direction once I leave town. How long is the final "SPEED LIMIT 45" sign in my direction in force before I can speed up to 55?

  • 1
    If you see "Speed Limit 55" facing you, then the speed limit is 55 MPH until you see the "Speed Limit 45" sign facing you. The "Reduced Speed Ahead" sign does not change the speed limit at all; it is just there to let you know that the limit could change soon. The signs facing the oncoming traffic are not relevant to you; in fact it's possible that the oncoming traffic could have a different speed limit, though that is rare.
    – Brandin
    Commented Jan 24, 2019 at 5:33
  • @Brandin Different speed limits is not possible in the UK (except on dual carriageways). Commented Jan 24, 2019 at 10:55
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    @mkennedy, given that the road in/out of town is rural for a long distance, it's safe to assume that people coming into town were indeed traveling 55 and now must slow to 45. What I can't figure out is at what point I can legally speed up to 55 after I leave town (passing the last 45 sign before hitting miles of unsigned rural road) Commented Jan 24, 2019 at 18:51
  • 1
    Maybe check out this map. It's hosted by the company I work for, but the data was provided by NCDOT.
    – mkennedy
    Commented Jan 24, 2019 at 19:14
  • 1
    If the limit does actually change to 55 at some point, the lack of a sign does not comply with the MUTCD ("At the downstream end of the section to which a speed limit applies, a Speed Limit sign showing the next speed limit shall be installed"), but I don't know whether that would have legal force in NC. You might be able to get a sign posted by complaining, however.
    – phoog
    Commented Jan 24, 2019 at 20:31

1 Answer 1


It is important to be certain about where that point is, because insufficient speed can earn you a ticket just as excess speed can. GS 20-141 makes it illegal to drive below 40 MPH in a speed zone of 55 MPH. However, if there is no posting of minimum speed, that restriction does not apply.

Under state law, the maximum speed limit is 35 MPH inside municipal corporate limits, and 55 outside corporate limits. DOT can raise or lower limits depending on whether they find that faster is still safe or the statutory limit is too fast, but the limits must be posted.

The municipality may have taken advantage of para (e)

Local authorities, in their respective jurisdictions, may authorize by ordinance higher speeds or lower speeds than those set out in subsection (b) upon all streets which are not part of the State highway system; but no speed so fixed shall authorize a speed in excess of 55 miles per hour. Speed limits set pursuant to this subsection shall be effective when appropriate signs giving notice thereof are erected upon the part of the streets affected.

Or, para (f)

Whenever local authorities within their respective jurisdictions determine upon the basis of an engineering and traffic investigation that a higher maximum speed than those set forth in subsection (b) is reasonable and safe, or that any speed hereinbefore set forth is greater than is reasonable and safe, under the conditions found to exist upon any part of a street within the corporate limits of a municipality and which street is a part of the State highway system (except those highways designated as part of the interstate highway system or other controlled-access highway) said local authorities shall determine and declare a safe and reasonable speed limit. A speed limit set pursuant to this subsection may not exceed 55 miles per hour. Limits set pursuant to this subsection shall become effective when the Department of Transportation has passed a concurring ordinance and signs are erected giving notice of the authorized speed limit.

When local authorities annex a road on the State highway system, the speed limit posted on the road at the time the road was annexed shall remain in effect until both the Department and municipality pass concurrent ordinances to change the speed limit.

Once you are outside the corporate limits, the corporation has no authority to modify the limits set by the state, and the state limit of 55 is applicable. There is no requirement to the effect that the corporation must tell you that you may now result your regular speed. It would be polite, but not legally required.

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