Level crossing safety and the Hierarchy of Controls

Railway level crossing safety in New Zealand is framed as ‘controlled’ vs ‘uncontrolled’, with ‘active’ or ‘passive’ crossing protection. ?

Another common paradigm for describing safety controls is the ‘Hierarchy of Controls’. The Hierarchy of controls uses the categories of elimination, substitution, engineering, administrative, and Personal Protective Equipment (PPE).

This article aims to compare and align these two paradigms. ?

The Railway Terminology:

TrackSafe New Zealand classify level crossings as protected, unprotected, and as having active or passive safety measures.

TrackSafe describe active measures as “barrier arms (either half or full), flashing lights or bells – or a combination of these”, while passive measures are “Stop signs or Give Way signs”.

Protected crossings are those that are protected by:

• "half-arm barriers plus flashing lights and bells”
• “flashing lights and bells”
• “either Give Way or Stop signs”

TrackSafe also note that level crossings can be grade separated where “engineering has physically separated the crossing".

The KiwiRail level crossing risk assessment guide aligns to this terminology.

While the term unprotected is not defined it is implied as being those crossings that do not have active or passive measures.

Here's a summary of the railway terms....

The Hierarchy of Controls

The Hierarchy of Controls (HoC) is the principle that there is an order of preference of safety controls categories based on their effectiveness (p.36).

While the wording in literature varies, I've distilled the definitions from multiple sources (1, 2, 3) into the following:

Hopefully there’s no disagreement on these definitions, though feel free to comment below.

Hierarchy of Controls and Level Crossing measures

The next step is to combine the two tables.

In preparation for this, I thought I’d ask others where they considered lights and bells (without barriers) sit within the HoC. I created a linkedIn poll which received 83 votes over a three-day period.

• 78% answered that ‘lights and bells’ are administrative controls. Comments suggested that lights and bells ‘do not create physical separation and rely on people recognising them’ and ‘there is no physical obstruction’.
• 22% answered that lights and bells are engineering controls. The supporting comments suggested ‘lights and bells are engineered and therefore engineering controls’, and ‘administrative controls are reserved for things like rules, policies, notices and procedures’.
• One rather clever respondent hedged their bets saying, “lights and bells are engineered administrative controls”.

Reconciling active measures and administrative controls?

There seems to be general agreement that a stop or give way sign is an administrative control. If we shine a light on the sign I'm sure most would still consider this an administrative control – it now has some minor electrical engineering.

If the light shining on the sign flashes, the sign is still an administrative control, now with slightly more advanced electrical engineering.

If we turn the light to flash toward the person, I argue this is still an administrative control – the light is just taking a different path.

We are still expecting the person to alter their behaviour.

Adding a bell brings our attention to the light, and still remains in the administrative category of altering behaviour.

I acknowledge that creating lights and bells on a mast requires more 'engineering' than stamping a metal sign and pouring a concrete base, though it still remains an instruction to the person which aims to alter their behavior and remains administrative.

The results

The table below aligns the HoC with the Railway Level Crossing controls.

Closing the road or the railway at the crossing eliminates the risk. Removal of the crossing also substitutes the risk from 'train vs person or car' to 'train vs train' or 'car vs car'.

Grade separation isolates the train from the people, and barrier arms provide a physical control defined by HoC as an engineering control.

Lights, bells, instruction signs (give way, stop), path markings, and rumble strips aim to change the way people act, are are administrative controls.

There doesn't seem to be any notion of PPE associated with level crossing safety.

What’s next?

Why have I done this? My next article will examine the stats on level crossings controls against the hierarchy of controls. This aims to explore the percentage of elimination, substitution, isolation, engineering, administrative controls across New Zealand's Railway Level Crossings.

Preliminary review of the data suggests we rely very heavily on administrative controls where we expect people to modify their behaviour, rather than higher order, and more effective, controls that provide some sort of physical separation.

I aim to have this published here in the next week or so, ahead of the New Zealand Rail Conference.