+ RMA Rural Municipalities
of Alberta

Resolution 11-17S

Review of Standard Practices for Installation of High Tension Cable Barriers on Two-Lane Provincial Highways

Date:
March 21, 2017
Expiry Date:
April 1, 2020
Active Status:
Active
Sponsors:
County of Barrhead
District:
3 - Pembina River
Year:
2017
Convention:
Spring
Category:
Transportation and Infrastructure
Status:
Intent Not Met
Vote Results:
Carried
Preamble:

WHEREAS the purpose of Alberta’s provincial highway system is to provide for the safe and efficient movement of people and goods; and

WHEREAS the diversity of vehicles and equipment on Alberta’s provincial highways ranges from vehicles operated by the general public to commercial, industrial and agricultural equipment; and

WHEREAS the Government of Alberta has identified High Tension Cable Barriers (HTCB) as the preferred barrier system and is a standard to replace the traditional guardrail systems where feasible; and

WHEREAS the Government of Alberta has conducted performance evaluations on the safety and operational performance of HTCB for use in medians between multi-lane roadways only; and

WHEREAS there is the potential for safety concerns created by having HTCBs installed on the shoulders (particularly both shoulders) of rural two-lane highways;

Operative Clause:

THEREFORE, BE IT RESOLVED that the Alberta Association of Municipal Districts and Counties urge the Government of Alberta to review Alberta Transportation’s Standard Practices for installation of High Tension Cable Barriers (HTCBs) on two-lane provincial highways to ensure Alberta has the safest possible highways.

Member Background:

Since 2012, the province has identified HTCBs as the preferred barrier system and a standard to replace the traditional guardrail system.  The province has advised that between 2014 and 2016 approximately 23 km of HTCB have been installed in the North Central Region.  These devices consist of metal posts fixed into the sides of the roadways, often being located very close to the driving lanes, with metal cables extending the length of the barrier.  HTCB height is generally 42 inches compared to the traditional guardrail at 28.75 inches or 32 inches high for new guardrails.

Evaluation of the safety and operational performance of HTCB installed in the median of multi-lane roadways has been conducted by several jurisdictions including Europe, New Zealand, United States and Canada.  In Alberta, the Deerfoot Trail project in Calgary in 2011 and the Highway 2 project in 2013 have provided relatively conclusive evidence that HTCBs significantly reduce cross-median collisions, nearly eliminate cross-median fatalities, and reduce the number of severe injury cross-median collisions with a general increase in property damage only collisions.  EBA Engineering Consultants Ltd. performed both evaluations and suggested that as a result of HTCBs the vast majority of head-on, sideswipe-opposite direction and off-road left collisions will be converted to median type crashes and that the median type crash severity is reduced due to the energy absorption characteristics of the flexible barrier system.

When HTCBs are installed in the median between multi-lane roadways the value of these devices is clear, so what is the problem?

When HTCBs are used on rural two-lane highways, the hazards created by HTCB are potentially much greater than the dangers they are meant to alleviate.

  • HTCBs are being installed on the right shoulder in both directions on two-lane highways which often have a narrower right-of-way and a narrower distance between the driving lane and the edge of the road surface.
  • Height of HTCBs makes it difficult for wide loads lower than approximately four feet to travel on the highway (see attached photo). Highways are very critical for the efficient movement of large equipment utilized in a variety of industries such as agriculture, oil and gas and manufacturing.  To deal with these challenges equipment operators will be forced to either drive down the middle of the roadway presenting a driving hazard for oncoming traffic that will have nowhere to go, or choose alternate routes using local roadways that may create access issues and cause damage to road surfaces.
  • Purpose of HTCBs on two-lane highways is to prevent motorists from entering the ditch, however in four-lane highways the focus is to prevent cross-over collisions. On a two-lane highway with HTCBs there is no escape from a cross-over (head-on) collision where oncoming traffic crosses the center line.
  • Evaluation of maintenance of HTCB installed in the median of a multi-lane roadway suggested mixed concerns regarding snow removal and mowing which may be enhanced when working on a narrower two-lane roadway. Concerns were related to safety of maintenance staff and/or ineffective snow removal.  Ineffective snow removal would only serve to make a narrow road even narrower.
  • HTCBs installed on narrower roadways may also hinder pedestrian and bicycle traffic.

Currently the County of Barrhead has two locations where HTCBs were installed by Alberta Transportation in conjunction with a road project.  Both locations require review based on the concerns above.  In addition, standards for installation of HTCB including placement and/or height, or potential alternatives must be reviewed on a site by site basis to ensure the safest possible highways in Alberta.

Attachment – Example of HTCBs on a two-lane highway in the County of Barrhead.

RMA Background:

The AAMDC has no active resolutions directly related to this issue.

Government Response:

Alberta Transportation:

Where there are hazards, a mitigation strategy is required to reduce the severity of incidents where vehicles run off the road. If the hazard cannot be removed, relocated, or modified, the next best option is to protect drivers from it. High Tension Cable Barriers (HTCBs) are proven to prevent or reduce the severity of crashes where vehicles run off the road. They are the most forgiving barrier system available for reducing the severity of off-road crashes, provided a suitable operating space is available.

An October 2016 design guide available on the Alberta open government portal includes guidelines for an HTCB installation in the median and on the roadside. This bulletin includes guidelines such as the placement, and the height on undivided highways, considering wide loads, farm equipment, and nuisance hits.

As outlined in the bulletin, it is best to set HTCBs as far back from a road as practical in the interest of accommodating wide loads, farm equipment, and reducing the frequency of nuisance hits. This approach provides more lateral space and reduced barrier height compared to an installation at the edge of a road.

A suitable flat slope on the side of the road allows for an offset between the edge of a shoulder and the barrier system. If a flat slope is not available, an HTCB must be placed at the pavement’s edge (the edge of the shoulder on unpaved roads).

Both the barrier height, and the lateral offset of an HTCB, affect the ability to accommodate wide loads and farm equipment. Designers have the following options:

  • Offset the barrier as much as possible from the shoulder, while still providing deflection room for any hazards.
  • Modify the slope in order to offset an HTCB down the slope. If the side slope cannot be flattened due to constraints, an HTCB can be placed at the shoulder break point. This is the same location where a conventional barrier system would be placed.
  • Specify that an HTCB must be 840 millimetres in height or less. This height aligns with the new height requirement for W-Beam barriers. This option minimizes the likelihood of nuisance hits from wide-load vehicles, including farm equipment. AT has various HTCB products available that meet this height requirement.

On two-lane highways, motorists’ ability to escape a cross-over (head-on) collision is not affected by the presence of an HTCB or a conventional barrier. In addition, HTCBs:

  • do not cause snow drifting to the same extent as traditional barriers, which results in reduced run-off-road incidents and maintenance costs related to snow clearing;
  • do not impede the movement of pedestrians and bicycles as much as that of conventional barriers on a road with a narrow shoulder; and
  • occupy less space than a conventional barrier, allowing for a wider shoulder.
Development:

The Government of Alberta’s response includes information detailing design options to ensure that HTCBs on two-lane highways are as safe as possible and do not impact snow removal or oversized vehicle travel on such highways. However, the resolution requests Alberta Transportation to review the current practices, which the response does not indicate a willingness to undertake.

This resolution is assigned a status of Intent Not Met and the AAMDC will continue to advocate on this issue.

Provincial Ministries:
Transportation
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