ITS service definition
Dynamic lane management (DLM) service enables a temporally modifiable allocation of lanes by means of traffic guidance panels, permanent light signals, multiple-faced signs, LED road markers, closing and directing installations, etc.
Fundamental applications of this service are:
ITS service objective
The overall objective of the dynamic lane management (DLM) service are:
ITS service radar
ITS service key words
Dynamic lane management (DLM) enables the number of lanes in one direction at a given point of the network to vary. Dynamic Lane Management techniques include the use of traffic guidance panels, permanent light signals, multiple-faced signs or prisms, lane lights, closing and directing installations and so on.
Dynamic lane management can be activated at fixed times or in particular conditions of heavy volumes of traffic, or in case of incidents, ad-hoc road work or other blockage on the specific lane, usually by means of variable message signs or other typologies of road signs.
To ensure that there are no blocks like broken-down vehicles or other objects on the lane or hard shoulder to be allocated, permanent video surveillance using Automatic Incident Detection is recommended, in particular for temporary activated systems (like reverse lane use).
Use of the Dynamic lane management (DLM) is differentiated according to the following fundamental applications:
Tidal flow system
A tidal flow system is defined as the dynamic management of lanes for one direction on road sections. This allows operators to temporally (daytime, event-based) react to different capacity requirements in different directions of route sections. These sections are delimited by means of transition areas at the beginning and at the end of the section. In the case of tidal flow systems, suitable control measures have to ensure that the lanes are released in one direction only and that “driving in the wrong direction” is excluded. The reversible allocation of an additional lane to one direction during peak hours reduces the traffic density per lane at equal inflow of traffic and therefore traffic flow is improved while the frequency and extent of incidents are reduced at the same time.
Lane allocation at the intersection
Intersections can be involved in lane signalization as long as the cross-section and the directional allocation of the respective lanes are kept in the intersection area. An additional lane allocation on the approach to signal-controlled junctions increases the traffic capacity and reduces congestion at unchanged green periods.
The target of dynamic lane management at access points to motorways is the variable management of lanes on the main carriageway and the access ramp. On the main carriageway, the right lane is closed for through traffic while at the same time the lane is provided as an additional access lane of the ramp. Thus temporally increasing capacity demands of entering/exiting traffic with low loads on the main carriageway are taken into account.
Lane allocation before and in the tunnel
The possibilities and application areas for dynamic lane management at entry links to and inside tunnels should guarantee safe and smooth traffic use of the tunnels as far as possible, both in the normal case and in case of incidents, construction and maintenance works. With this aim the traffic is guided on to the counter flow lane, the so-called counter-flow operation, and guided together with the traffic in the contra-flow tube lane in case of closures in the tunnel or total closure of a tunnel tube.
Hard shoulder running
Temporary hard shoulder running provides a significant capacity increase of the crossroad section. In order to exploit the benefits of the higher capacity of hard shoulder usage, and to minimize the safety loss due to the removal of the hard shoulder, certain preconditions have to be fulfilled before the release (technical equipment, proof of economic efficiency, provision of emergency stops, infrastructure conditions).
Lane clearance ahead of road-works sites
Variable message signs (VMS) or dynamic prisms are used here to protect work teams on the roads/ motorways. This use of VMS or dynamic prisms for dynamic lane management (DLM) helps to keep traffic flowing smoothly because drivers know what is happening some hundred metres ahead of the road works site and have enough time to change lane without the need to brake. Furthermore, this procedure represents an additional element of safety for road workers.
Lane clearance due to incidents
For this typology of dynamic lane management (DLM) existing VMS are used to guide traffic from the lane impacted to neighbouring lanes in advance of the incident location and thus to assist police on the road/motorway. Agreements should be concluded with Police, Traffic Officers or rescue staff (according to the system applied in each country) in order to activate VMS and to agree in advance the content of the messages on the VMS.
The overall objectives of Dynamic Lane Management (DLM) services are:
In most cases, Dynamic Lane Management provides options for road managers with a temporary increase or decrease of road sections (working sites and incidents are exceptions to ensure the safety for road users). DLM is meant to be implemented on road sections or network areas concerned with highly varying traffic loads and capacity issues.
The tidal flow system is appropriate on sections without any kind of built lane separation. Otherwise, crossover sections have to be deployed according to the network geometry, e.g. before tunnel sections.
DLM is concerned with the misuse or unclear instructions given to road users through VMS or fixed signs. Therefore, road operators should be concerned with information display with the intent to inform users in the least ambiguous way (VMS, fixed signs or traffic lights). Road operators should also focus on safety precautions before activating the DLM services.
From a global perspective, DLM measures have the positive effect of limiting congestion in a specific spot.
According to the different implementations of DLM, specific objectives are:
Note: Hard shoulder running is a specific application case of dynamic lane management. A dedicated ITS Core service profile describes this application, consequently the present DLM service description doesn’t present any information, requirements or recommendations dealing with this specific application. They are described in the Hard shoulder running service description (see TMS DG04).
Relevant information for this service is:
“Dynamic lane management (DLM) service enables a temporally modifiable allocation of lanes by means of traffic guidance panels, permanent light signals, multiple-faced signs, LED road markers, closing and directing installations, etc.
Fundamental applications of this service are: tidal flow systems, lane allocation at intersections, lane allocation at tunnels, hard shoulder running.”
Dynamic lane management (DLM) provides a way of optimizing the capacity of existing roads by using dynamic devices that affect vehicle flow by assigning the number of lanes that are open or the types of vehicles that are authorized.
The service is mainly applicable along the network characterised by:
The additional following main parameters are generally taken into consideration for the deployment of this service:
Dynamic lane management can be deployed on motorways, 3 or 4 lane roads, corridors, peri-urban motorways, critical spots. In most cases (if not in the standard case) DLM is a part of a traffic control system and needs to be coordinated with other systems (i.e. speed limit, incident warning, hard shoulder running, HGV overtaking ban).
Figure 44 shows the interface architecture of the Dynamic Lane Management service.
Figure 45 shows the typical functional and information architecture of the Dynamic Lane Management service.
Sub-function “Prepare implementation”
Sub-function “Data collection and analysis”
This sub-function includes traffic monitoring and road clearance control. The devices and methodologies for traffic data collection are not covered by this service description. They depend amongst others on the particular used data collection system and are left to the operator to select.
Sub-function “Traffic guidance to users”
The implementation of Dynamic Lane Management comprises different applications:
Independently of the initial objectives, the expected benefits of the service mainly rely on the implementers’ involvement and the end users’ acceptance.
DLM usually involves a range of partners such as road authorities, road operators, the police, the fire brigade, ambulance services, recovery services and the media. Performance of the DLM process relies on an overall cooperation. This cooperation should be initiated some time before the operation of the DLM service to ensure service continuity and quality display of the DLM service.
The dynamic management of lanes is displayed to users by means of Variable Message Signs. When dealing with cross-border or cross-regional dynamic lane management (DLM) systems, Variable Message Signs display should be as harmonised as possible so as to be more comprehensible to users. The display is usually located overhead (VMS mounted on traffic sign gantries) or laterally in single cases (VMS mounted on masts) besides the carriageway.
The compliance rate and the acceptance of systems with dynamic lane management (DLM) by the car drivers may vary heavily dependent on the comprehensibility of the operated switching. It should therefore be checked and improved, if needed, by a comprehensive quality control.
End-user acceptance of the system can be improved by deploying Variable Message Signs which provide users with detailed information of how to behave on the section affected by dynamic lane management (DLM). Such information, given to the users progressively, can make them feel safer: in the case of hard shoulder allocation, for instance, users should be informed in advanced that the system is active, how they can profit from an added lane opened (or in the case of HGV how they are obliged to keep to the inside lane), how they have to reduce speed, how long an additional lane is sustained and when the system reduces lane availability again. The more the system is comprehensible for users, the more they accept it.
All measures can then be considered to be successful when users easily understand them and traffic flow is kept under control.
In the process of harmonisation, Dynamic Lane Management is part of a traffic control system and the requirements listed below are some general requirements to be fulfilled when Dynamic Lane Management is activated. It has to be considered that DLM deals with a lot of different situations and in some cases exceptions must be possible.
Common Look & Feel requirements:
Tidal flow system requirements
Common look & feel requirement:
Common look & feel requirements:
Lane clearing ahead of working sites
The deployment of the dynamic lane management (DLM) requires a minimum infrastructure.
Variable message sign standards:
The most relevant standards in Europe concerning technologies and systems examined by this guideline are EN 12966-1/2/3:2005. Road vertical signs – Variable message traffic signs. These include:
Information provision standards:
Table 26 gives the Level of Service recommendations for a Dynamic Lane Management service. The background of this concept is descripted in chapter 2.6.
Table 26: Level of Service recommendations for Dynamic Lane Management
Note: Attention must be paid to Level C of “Display of traffic information (support)” because it could create information overflow if not well organised.
Each level shows a technical advancement, but a higher level is not necessarily better than a lower level.
Level of service requirement:
Table 27: Levels of Service related to Operating Environments (see also chapter 2.5.3 and ANNEX C)