Urban Transport Strategy. Management in Developing Countries John A Cracknell, страница 113

§  Manual intervention by the traffic police on traffic signal controlled junctions occurs in some cities where traffic congestion is severe (in the past in Bangkok, Manila, etc).  Such practice should be discouraged/prevented as traffic police are unable to assess either interaction between junctions (even though radio contacts are used) or understand the concept of saturation flow on which traffic signal design-capacity is based;

§  Simple channelisation at signal controlled and other junctions separates traffic conflicts, controls angles of potential traffic conflict, accommodates traffic turning movements safely, protects pedestrians and provides them with facilities to cross one traffic stream at a time, enables traffic control devices (signs, signals etc) to be mounted appropriately and protect them from traffic damage, discourages prohibited traffic movements and so on.  The cost is small and the benefits large.  However, in many developing cities, there is reluctance to use “heavy” channelisation and junctions are “spread out” resulting in undirected traffic movements and conflicts, safety problems pedestrian problems; much greater use of “heavy” channelisation will increase capacity and safety;

§  Pedestrians are often not provided with facilities to cross at signal controlled junctions.  There is a wide range of options – simple pedestrian phases within the signal cycle, channelisation/islands to allow pedestrians to cross part of the road rather than full road width, removal of kerbside obstructions so that pedestrians have good visibility and are not impeded from crossing, ancillary pedestrian signals close to, and connected to, the main signals etc; greater attention to pedestrian needs at junctions is required in many cities;

§  Road markings can do much to improve junction efficiency.  It is recognised that driver discipline may not be particularly good in some cities but even so, well set out road markings (i) can make a significant difference to junction operations and (ii) assist the traffic police by providing a base for enforcing traffic regulations (e.g. by marking turn lanes with turn-only arrows and signs)

§  Lane balance and consistency of layout – it is not uncommon to find fewer lanes downstream of a junction than on the approach (aside from turn only lanes); this can cause traffic conflicts and safety problems on the immediate exit to junctions and can result in capacity reduction; a junction program should seek to ensure lane balance at junctions and if changes in road cross sections are inevitable, make the transition away from junctions

§  Instances have occurred where grade separation of junctions has been introduced without due regard for (i) downstream effects – traffic queues are simply transferred, (ii) impacts on bus services – buses cannot usually use flyovers or underpasses as bus stops cannot be provided and thus passenger objectives are not met and often, the remaining ground level road is reduced in capacity with adverse impacts on buses; improvement of junctions by grade separation needs to be placed in the context of the immediate surrounding network and the impact on all users needs to be recognized.

Rationale and Objectives - Compliance with traffic regulations by all road users is essential to ensure (i) road safety, (ii) efficiency of traffic movement and (iii) that traffic management schemes operate as planned.  Compliance with traffic regulations depends largely on driver’s perception of risks and the implications of being subject to enforcement action.  Traffic schemes work best if they are designed to be “self enforcing” (where traffic movements are controlled as far as practicable by physical measures such as islands, medians, channelisation etc) but contravention of regulations can be deterred by making the penalties imposed for offences severe.  Many traffic schemes fail to realise their potential due too poor enforcement and this applies particularly to schemes which provide priority to one category of vehicle such as bus lanes or bicycle lanes.  The objective of enforcement is to