Page:UK Traffic Signs Manual - Chapter 8 - Part 1 (Traffic Safety Measures and Signs for Road). Designs 2009.pdf/161

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Table 6.3 Lanes 1 & 2 into lanes 3 & 2

and

	Temporary mandatory speed limit
	30mph		40mph		50mph
Step increase	Crossover length (m)	Paved length (m)	Crossover length (m)	Paved length (m)	Crossover length (m)	Paved length (m)
0	126	90	153	99	180	117
3	207	135	252	162	297	198

Table 6.4 Lanes 2 & 3 into lanes 3 & 2

and

	Temporary mandatory speed limit
	30mph	40mph	50 mph
Step increase	Crossover length (= paved length) (m)	Crossover length (= paved length) (m)	Crossover length = paved length) (m)
0	108	126	153
3	180	216	261

D6.6CHANGEOVERS

D6.6.1 TA 92 "Crossover and changeover design" (DMRB 8.4.6), which provides advice on changeover design, uses the concept of design speed for changeovers. This speed is directly related to the temporary mandatory speed limit of the road rather than the permanent speed limit and TA 92 gives details of this relationship. The distances given in Tables 6.5 and 6.6 are given in terms of the temporary mandatory speed limit.}}

D6.6.2 Table 6.5 below may be used to calculate the changeover length required for roads with a permanent speed limit of 50 mph or more depending on the design speed and the number of lane changes. A smooth '5' shaped curve to suit the site conditions should be used. The lengths have been calculated from TA 92 and rounded up to the nearest 9 metres for ease of use. If a shorter changeover is required, then advice from TA 92 should be used.

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