User:Martinvl/TOTSO

TOTSO – An acronym for “Turn Off To Stay On” which describes the pathway taken by a route through a junction where the driver has to Turn off the principal carriageway in order to stay on the route. The word is widely used by British and Dutch road enthusiasts regardless of whether a junction is grade-separated or not. It has found its way into a number of English, Dutch and German language Wikipedia articles. At the time of writing, no equivalent term from the Highways Agency or other official organization had been found in the public domain.

Causes of TOTSOs

Four principal causes of TOTSOs have been identified.

• The principal flow of traffic does not follow the route number and the junction has been designed to facilitate traffic flow. Examples include both of the M6 motorway/M6 Toll junctions.
• At the ends of a multiplexed section of carriageway, one of the roads splits off from the other. This situation does not occur in the United Kingdom as there is a policy that any section of road only carries one route number ("hiding of multiplexes" - the author's terminology).
• An unfinished route where the route is diverted onto other roads. Although this scenario occurs on many Continental roads, the policy of "hiding" multiplexes in the United Kingdom prevents it happening there.
• The junction in question was designed to accommodate a different route numbering system. This is by far the most usual cause of TOTSOs in the United Kingdom. It is also the reason that many Euroroutes have TOTSOs, such as the A4/A44 junction in Germany, close to the city of Aachen. The A4 was designed to pass through Cologne to the Netherlands, but the E40 which passes through Cologne en route to Belgium has a TOTSO at this junction in order to turn southwards.

Notable British TOTSOs

TOTSOs can occur at free-flowing junctions or at intersections. This list shows examples of each.

• M25 motorway

The TOTSO at Junction 5 of the M25 came into being when, in 1975, the proposed Ringway 4 and A25 Relief Road plans were merged into a single plan. The original plan was that Ringway 4 would be the outermost ring road around London and that the A25 relief road would run from Watford to Maidstone take through traffic from the M1 to the M20 avoiding London. It was dubbed the M25 because it ran parallel to the A25 for a significant part of its route. Ringway 4 was to be called the M16. When the plans were merged, contracts were already out for that part of the M25 close to the present Junction 5, so the eastward section was renamed the M26 and the new M25 route joined the westward section via a TOTSO.

• M60 motorway

The TOTSO at Junction 18 of the M60 came into being when the short stretch of motorway linking the current Junction 19 to Junction 20 of the M60 was completed and simultaneously sections of the M60, M66 and M61 were renamed as the M60, giving Manchester an orbital road. However the point where the M62 crossed the M66 did not lend itself to being redesigned as principal carriageway and new M60 followed a route around the junction roundabout.

• M6 motorway

The section of the M6 that passes through the built-up area of the West Midlands was built in the 1970's. In the 1990's through traffic was frequently held up by local traffic, making a by-pass an attractive proposition. The resulting bypass was the M6 Toll and to encourage through traffic to use it, Junctions 4a and 11a of the M6 were re-engineered to make the new road the route of choice, creating TOTSOs on the M6 at either end of the toll road.

• A30/A303 junction

For many years the A30 was the preferred route from London to Exeter and beyond. In 1946, when it became apparent that many of the towns and villages through which the A30 passed would need by-passes, it was decided to merge a number of small roads into a single new road, the A303, which would bypass all the towns and villages between Basingstoke and Honiton on a single road. The point at which the A303 rejoins at the Honiton end has been re-engineered to create a TOTSO so as to encourage through traffic to use the A303 in preference to the A30.