4.5 TMS-04 Hard Shoulder Running

4.5.1 ITS service at a glance

ITS service definition

Hard Shoulder Running (HSR) enables the dynamic temporary use of hard shoulders at road sections, including at junctions with the aim to increase road capacity when necessary. Hard Shoulder Running could be considered similar to the creation of an extra lane, but with specific safety issues due to the fact that a hard shoulder in common understanding is not available for general traffic use, and is sometimes replaced by refuges where road users can stop in an emergency or in case of breakdown.

Hard Shoulder Running is triggered by traffic demand, at fixed times or due to automated or manual requests and applied typically to bottlenecks, locations with poor safety records with a recurrent – but not constant – lack of capacity.

ITS service objective

The objective of Hard Shoulder Running is to increase road capacity on a section of the road network necessary, in order to minimize (heavy) congestion and to reduce the probability of congestion caused by incidents.

ITS service radar

ITS service key words

  • Hard Shoulder Running
  • HSR
  • Capacity
  • Congestion
  • Peak
  • Efficiency
  • Lane
  • Signal
  • Safety Protocols
  • Dynamic
  • Temporary
  • Demand Controlled

4.5.2 ITS service profile General ITS service description

The hard shoulder running service enables dynamic temporary use of hard shoulders. 

Hard Shoulder Running should only be implemented when the safety level remains the same or improves against the current operational mode. It can be applied on network areas, route sections and junctions prone to capacity problems. The capacity problems can be on a regular basis (e.g., Tuesday versus Friday, peak hour versus off peak hour) or for a longer period (major road works). The Hard Shoulder Running should cover the entire bottleneck, thus start at a junction with major entering flows and end at a junction with major flows leaving the road. Otherwise, the roads upstream and downstream of the HSR section may need to cope with extra capacity requirements as a result of potential higher demands.

The measures must include strict safety precautions in order to maintain the existing safety levels and can only be deployed if specific criteria are met, such as “no expected increase in emission levels”.

In a normal situation a hard shoulder has a specific set of users, mainly road users in emergency/ breakdown situations. Opening the hard shoulder to all road users can cause problems for emergency users and therefore their needs must always be considered. 

Opening the hard shoulder for regular traffic without additional measures could give the hard shoulder an ambiguous character. This can cause confusing situations for road users, some examples of which include:

  • A commuter accustomed to an open hard shoulder during peak hours, may also expect it to be open during off-peak hours and in lower volume peak hours in holiday periods. 
  • A commuter who is accustomed to an open hard shoulder during peak hours may use it while it is closed due to an emergency/breakdown situation downstream.
  • Road users who are unaware you are allowed to drive on the hard shoulder will not adapt to a new lane, which can cause dangerous situations and under-utilisation of the hard shoulder lane by the user. 

Good unambiguous instructions and education can counter these problems. What is the vision?

The vision for use of Hard Shoulder Running is to increase road capacity on a necessary section of the road network, in order to minimize (heavy) congestion and to reduce the probability of congestion caused incidents. The level of throughput of traffic should increase due to the increase in road space. What is the mission?

The mission for Hard Shoulder Running:

  • is for bottlenecks/problem areas in the network with recurrent, but not constant, lack of capacity, i.e., recurrent peak hour congestion, to be eased and the benefits of extra capacity delivered to road users.
  • to provide additional capacity without the need to undertake costly and often more time consuming permanent widening of the carriageway.

Hard Shoulder Running is similar to creating a dynamic extra lane triggered by traffic demand, at fixed times (peak hours) or even manually, and therefore requires dynamic traffic management control (see also TMS-01 Dynamic lane management). This extra lane is also to be controlled in the case of the use of the hard shoulder by a broken-down vehicle.

In specific cases Hard Shoulder Running:

  • can be used to variably assign the lanes of the main carriageway and the exit ramp at the end of the Hard Shoulder Running segment (combination with Dynamic Lane Management).
  • can be used to keep the number of lanes in case of left lane clearance ahead of working sites at the median
  • can be referred to as peak hour lanes. It should be noted that these can also imply extra lanes, which are not necessarily hard shoulders
  • can be conceived as an interim solution until an appropriate traffic solution is in place to counter capacity problems
  • can be used for dedicated lanes, thus creating extra capacity for a dedicated set of road users like public transport (application case not covered by this service description, see also TMS-01 Dynamic lane management). Distinctiveness to other ITS-services

Hard Shoulder Running is a special application of dynamic lane management. As a special service it interacts with the following other European ITS Core services:

  • TMS-02 Variable Speed Limits
  • TMS-01 Dynamic Lane Management
  • TMS-06 Incident Warning and Management

Note: By applying Hard Shoulder Running, incident warning and management becomes very important and can become more complex. In this instance an extra step in the incident warning and management process is needed, i.e., to check if the hard shoulder is clear or can be cleared prior to opening of the hard shoulder to traffic. This also applies to ensure that proper winter maintenance has been carried out at winter time before opening the hard shoulder.

4.5.3 Harmonization requirements and advice  ITS Service Definition

Hard Shoulder Running enables the temporary use of hard shoulders along road sections. To achieve this overhead signals or signs at the roadside at regular intervals are used to indicate whether a hard shoulder is open for normal traffic. Furthermore, variable message signs are used to inform road user of current traffic conditions and in most cases the imposition of reduced speed limits which can be mandatory. Furthermore, lane signals at regular intervals – if present – can be used to indicate whether a hard shoulder is open for normal traffic.

Hard Shoulder Running is triggered automatically by traffic demand, at fixed times or due to manual requests and applied to bottlenecks, locations with poor safety records with a recurrent – but not constant – lack of capacity. Functional requirements and advice Functional architecture

Figure 65 shows the typical functional architecture and control flow of a “Hard Shoulder Running Service”.

Figure 65: Functional architecture and control flow of Hard Shoulder Running

Hard Shoulder Running is carried out with a control algorithm or by using a manual request according to pre-determined traffic conditions such as high traffic demand.

Hard Shoulder Running is carried out via the following (illustrated by examples) processes:

  • Monitoring –  Collect real-time information on the traffic situation of the network or relevant/ chosen route sections.
  • Safeguarding – Check that the hard shoulder is unobstructed for safe use. The hard shoulder must be free of debris, ice and snow, and vehicles obstructing safe use of the hard shoulder. Also, no road maintenance or road works can be conducted on the hard shoulder during periods of running.
  • Information – Inform road users that the hard shoulder is open for running. Dynamic road signage provides road users with instructions that the hard shoulder is open for use.

If a lane control system is available, active signage above each lane and the hard shoulder should be used.  A symbol, such as a green arrow pointed downward and/or variable speed limit signs identifying open lanes and the allowed maximum speed, respectively, equally indicate that the hard shoulder is open for use; however, these symbol types (e.g. arrows or speed limits) cannot be used interchangeably at one location. Activated overhead signs dynamically indicate the total number of open lanes and whether the hard shoulder is open for use as an additional lane. Another option is the use of dynamic roadside signage to provide road users with instructions that the hard shoulder is open for use. Either option can be used or both can be used simultaneously to support the dynamic signage inform road users that the hard shoulder can be used for driving.

  • Information – Inform road users that the hard shoulder is closed or being closed. If a lane control system is available, a yellow (flashing) arrow pointing diagonally downward is used as a transition signal to start the clearing process of hard shoulder. The clearing process can take place through a lane change along the extent of the road section and/or simultaneously via an exit ramp. Functional requirements and advice

Functional requirements:


  • FR1: Incident detection and verification must be possible for the whole Hard Shoulder Running section. Incident detection does not need to be automated.
  • FR2: Detection and verification time, as well as reaction time, should be as short as possible.
  • FR3: Safety protocols and instructions must be documented and used to ensure the opening, running and closing of the Hard Shoulder Running is done safely.
  • FR4: In case of failure of the Hard Shoulder Running signalization the system must be entered immediately into a safe state.
  • FR5: Good quality surveillance and monitoring functions for traffic operators should be implemented.

Traffic monitoring and decision

  • FR6: Before starting the Hard Shoulder Running opening/closing procedure, continuous traffic monitoring should be carried out along the entire section of Hard Shoulder Running including the hard shoulder as well as upstream and downstream road sections (network effects).

Functional advice:

  • The hard shoulder can also be used on a regular basis for specific type of vehicles, e.g. public transport. This application case is not covered by this “Hard Shoulder Running” service guideline. Further, there are examples within Europe where the hard shoulder has been converted for permanent running. This case is not covered by this guideline.

Feasibility study

Before implementation of a Hard Shoulder Running traffic management services a feasibility study will be able to answer the following questions:

  • Is it necessary? 
    •  Sometimes extra capacity is only needed for 2 or 3 hours one day of the week. The costs of implementing a scheme should not outweigh the benefits. Although HSR has become mature in some European Road Authorities, reduced speed limits when HSR is in operation can sometimes be perceived as a delay by drivers if there is no need for it. As such careful attention needs to be paid to the control algorithm to ensure the system is credible for road users.
  • Will it benefit traffic flow on a network level? 
    •  Studies of real-life systems show that an increase in capacity may only result in a limited impact on congestion, although journey times may become more reliable, and in some instances safety improved. Extra road attracts extra road users. Therefore, a comprehensive traffic analysis should be performed to ensure that the existing bottleneck is entirely addressed by the measure. Furthermore, simulation of the situation is recommended to ensure that the measure can cope with the demand in order to avoid negative network effects  both upstream and downstream.
  • It is allowed? 
    • Air and noise pollution legislative rules are strict (see also EU-legislation). Inhabitants in the area or a near extinct fauna or flora can put plans on hold for years.
  • Is the hard shoulder construction suitable? 
    •  Construction of the hard shoulder must be suitable for a heavy traffic load or construction may have to be improved and issues regarding drainage of water from the road surface must be solved.
  • Is deployment safe? 
    •  How is safety guaranteed or improved? Are, for instance, safeguarding protocols for the deployment of Hard Shoulder Running available and suitable? HSR will require formulation and use of a safety protocol for day-to-day operations.
  • Does the network have sufficient capacity?
    • The network must be able to cope with extra capacity demand both upstream and downstream. Increasing the capacity of a single stretch within the network, not considering upstream and downstream sections and intersection capacity, has only limited impact. Simulations of different scenarios are recommended.
  • Does the road authority have capacity?
    •  Day-to-day operation of HSR will result in operational overhead often meaning additional staff and more comprehensive technical infrastructure which will need to be monitored and maintained.
  • Do the Delegated Regulations under Directive 2010/40/EU have an impact?
    •  Delegated Regulation No 886/2013 addresses the need to provide road safety related minimum universal traffic information. Traffic management methodologies used for HSR will inevitably include use of VMS and other channels to communicate traffic management information and in doing so, safety related information such as an unprotected vehicle that is on the hard shoulder or elsewhere will need to be published by local or national access points (NAPs).  Furthermore, Delegated Regulation No 2015/962 address the provision of real-time traffic information services published via a National Access Point. Introducing HSR will necessitate collection, use of, and communication of raw or processes data. Certain information will require wider publication via a NAP, which will also have the effect of improving the HSR traffic management services to end users.

Hard Shoulder scheme evaluation

Following implementation of an HSR scheme, evaluation of the scheme will indicate how successful the scheme has been and whether the HSR services should be expanded other otherwise. 

Quantitative evaluation

To measure the impact of Hard Shoulder Running on safety, network efficiency and environment, it is necessary to collect data from the scheme using a proven methodology.

Suggested data for evaluation:

  • Monitoring data 
    • Congestion
    • Traffic volumes and speed
    • Work sites including maintenance work
    • Incidents 
    • Weather conditions
    • Road conditions (snow, ice, oil, salt…)
  • Logging of Hard Shoulder Running
    • Date
    • Start time/end time
    • Reason for releasing (opening) hard shoulder
    • Reason for closing hard shoulder
    • Congestion level
    • Speed limit
    • Average speed
    • Duration —Logging failure notices
    • Failure of the systems
    • Switching command which has not been carried out
    • Improper command

Qualitative evaluation

  • From a qualitative point of view questionnaires can be prepared and distributed in order to know road users’ perception of safety and network efficiency. Compliance of the road user is relevant aspect of network efficiency. The percentage of vehicles driving on the hard shoulder determines the extra capacity.”
  • Road operators could also be addressed with such questionnaires, differently formulated, in order to share their experiences on the impact of the dynamic allocation of lanes on the environment, safety and traffic flows. Interface requirements

Interface requirements:

  • IFR1: If the Hard Shoulder Running service provides hard shoulder information at interface 1 (see Figure 65), it must provide coded Hard Shoulder Running information including the following elements:
    • Location (section) of the Hard Shoulder Running section
    • Status of the hard shoulder (open/close)
    • Speed limit
    • Type of vehicles 
  • IFR2: If interface 2 is implemented, the Hard Shoulder Running service must provide at interface 2 (see Figure 65) Hard Shoulder Running information coded in C-ITS messages including the following elements:
    • Allocation and spatial dimension of the Hard Shoulder Running section
    • Road signs for Hard Shoulder Running (HSR is open, HSR is clearing)
    • Road signs for variable speed limit
    • Type of vehicles
  • IFR3: Incoming DENM from end users/vehicles are checked for safety-relevant facts that lead to the HSR being switched off or prevented from being switched on (e.g. stationary vehicles on the hard shoulder, obstacles on the hard shoulder lane). When relevant, the Hard Shoulder service should collect at interface 3 (see Figure 65) C-ITS coded Probe Vehicle Data information such as travel speed, direction, current location of a vehicle (microscopic traffic situation) relevant to this ITS Core service. Organisational requirements and advice

In general, it is necessary for national and European law and legislation to allow for the use of hard shoulders (AGR- European agreement on international main arteries, Annex II, section III.3.2). 

Per Member State different organisational standards and guidelines are used for hard shoulder measures. This does not necessarily affect the uniformity of the service for the road user.

Organisational advice:

  • Introducing HSR can raise safety concerns amongst police and road user communities. It is suggested that a dialogue is opened with key stakeholders at an early stage of evaluation and planning to enable them to give their specialist input. It is recommended that a pilot scheme is first introduced to allow learning from the scheme and adaptations to be made for incorporation into future deployment of HSR schemes. Common Look & Feel requirements and advice

Common Look & Feel requirements:

  • CL&FR01: The display of signs/pictograms on VMS or other end-user devices should be in accordance with prevailing national road codes and:
    • Member States which ratified the Vienna Convention MUST respect the Vienna Convention and the European agreement supplementing the convention (1st May 1971) and SHOULD consider the Consolidated Resolution on Road Signs and Signals (R.E.2).
    • Member States which did not ratify the Vienna Convention SHOULD follow the Vienna  Convention and also consider the R.E.2.

Common Look & Feel advice:

Driver information:

  • The road user should be informed on the road, but also in a general way, of the goals and functionality of Hard Shoulder Running services.
  • Lane colouring: In order to emphasize the presence of the lane for Hard Shoulder Running, a different colour of the tarmac may possibly be applied.

Common Look & Feel requirements:

  • CL&FR02: Safe havens/ERAs should be provided in order to create safe zones for broken down vehicles.
  • CL&FR03: Safe havens/ERAs should ensure a safe use (length and width). 
  • CL&FR04: The maximum distance between safe havens/ERAs should be 1000m. 
  • CL&FR05: Road markings at junctions and cross sections should be in line with general standards used for road sections without Hard Shoulder Running.
  • CL&FR06: Indications for an open or closed hard shoulder should be located at a distance which ensures the road user has good visibility of the successive signals/signs along the relevant stretch of road.

Hard Shoulder Running signage

  • Messages that should be conveyed to the road user through VMS, in car data or other means:
    • Hard shoulder is closed (CL&FR07)
    • Hard shoulder is open (CL&FR08)
    • Hard shoulder is clearing (CL&FR09)
    • End of the hard shoulder section (CL&FR10)
    • Applicable speed limit (mandatory or otherwise)
    • Adjustable direction signs (if overhead signs show the number of lanes)

Note: In some cases, the use of static signs can be sufficient. This is an option for Hard Shoulder Running that is used at set times (i.e. weekdays – 7:00-9:00)

Common Look & Feel requirements:

  • CL&FR07: Hard shoulder is closed should be displayed according to either Figure 66 or Figure 67
  • CL&FR08: Hard shoulder is open should be displayed according to either Figure 68 or Figure 69
  • CL&FR09: Hard shoulder is clearing should be displayed according to either Figure 70 or Figure 71
  • CL&FR10: End of hard shoulder section should be displayed according to either Figure 72 or Figure 67
Figure 66: Variable message signs for CL&FR07-1
Figure 67:  Support through dynamic lane management systems for CL&FR07-2 and CL&FR10:
Figure 68: Variable message signs for CL&FR08-1
Figure 69: Support through dynamic lane management systems for CL&FR08-2
Figure 70: Variable message signs for CL&FR9-1
Figure 71: Support through dynamic lane management systems for CL&FR9-2
Figure 72: Variable message signs for CL&FR10

Information provision standards:

  • IPS1: If a Hard Shoulder Running service is implemented at interface 1, the information (see IFR1) must be profiled based on EN 16157-3:2019 using the DATEX II Recommended Service Profile for Hard Shoulder Running.
  • IPS2: When relevant, Hard Shoulder Running information (see IFR2) should be profiled in an IVIM (infrastructure to vehicle information message) based on ISO 19321 using the C-ROADS C-ITS Message Profiles for the In-Vehicle Signage service.
  • IPS3: When relevant, the Probe Vehicle Data (microscopic traffic situation) information (see IFR3) should be collected, which is profiled based on ETSI EN 302 637-2 using the CAR2CAR Communication Consortium Basic System Profile. Level of Service definition Level of Service Criteria

Table 32 gives the Level of Service recommendations for a Hard Shoulder Running service. The background of this concept is descripted in chapter 2.6.

Table 32: Level of Service recommendations for Hard Shoulder Running Level of Service Criteria related to Operating Environment

Level of service requirement:

  • LoSR1: In the case that pre-deployment surveys / evaluations provide the necessary evidence to proceed with the deployment of the ITS-service “Hard Shoulder Running”, the minimum and optimum LoS should respect the following Level of Service to Operating Environment mapping table.

Table 33: Level of Service to Operating Environment mapping table (see also chapter  2.5.3 and ANNEX C)