Plain language law

New Zealand law explained for everyone

Land Transport Act 1998

Proceedings enforcing responsibilities - Evidence

146B: Weighted average speed limit between 2 detection points

You could also call this:

“Calculating the average speed limit for a road with changing speeds”

This part of the law talks about how to figure out the speed limit when there are different speed limits between two points on a road. This is important when the police want to check if you were speeding.

If there are different speed limits between two points where your speed is being measured, the police will use something called an “average weighted speed limit”. This is a special way to calculate the speed limit that takes into account all the different speed limits on that stretch of road.

To work out this average weighted speed limit, the police use a special math formula. They look at how long each part of the road is and what the speed limit is for each part. Then they do some calculations to come up with one speed limit number for the whole stretch of road.

The result of this calculation is rounded up to the nearest whole number, and that becomes the speed limit they use to check if you were speeding.

This text is automatically generated. It might be out of date or be missing some parts. Find out more about how we do this.

This page was last updated on

View the original legislation for this page at https://legislation.govt.nz/act/public/1986/0120/latest/link.aspx?id=LMS943111.

Previous

146A: Average speed treated as actual speed, or

"Police can use your average speed between two points as proof of speeding"

Next

146C: Evidence relating to average speed, or

"Law explains how your average speed can be used as proof in court if you're caught speeding"

Part 10 Proceedings enforcing responsibilities
Evidence

146BWeighted average speed limit between 2 detection points

  1. This section applies if more than 1 speed limit applies between 2 detection points on a length of road along which the average speed of a vehicle is to be calculated for the purposes of section 146A.

  2. The speed limit for the purpose of that calculation is the average weighted speed limit calculated under subsection (3).

  3. The average weighted speed limit for a length of road between 2 detection points is to be calculated using the following formula (and expressed in kilometres per hour rounded up to the next whole number):

    dt ÷ ((d1 ÷ s1) + (d2 ÷ s2) + ... (dn ÷ sn))

    Where:

    • dt dt

      is the surveyed distance (expressed in metres and rounded down to the next whole number)

    • d1, d2 ... dn d1, d2 ... dn

      are the intermediate surveyed distances (expressed in metres and rounded down to the next whole number) over which the speed limits between the 2 detection points apply

    • s1, s2 ... sn s1, s2 ... sn

      are the speed limits that apply between the 2 detection points.

Notes
  • Section 146B: inserted, on , by section 30 of the Land Transport (Road Safety) Amendment Act 2023 (2023 No 62).