PSS - Progressive Safe System

Transport for London (TfL) has implemented the Direct Vision Standard(DVS) and HGV Safety Permit Scheme[1], which require drivers of trucks weighing over 12 tonnes to obtain a safety permit before entering and traveling within Greater London. Failure to comply may result in a Penalty Charge Notice (PCN).

Starting on 28 October 2024, the DVS requirements will change. Under the new DVS 2024 standards, all zero-star, one-star, and two-star vehicles operating in London must be equipped with a Progressive Safety System (PSS).

What is PSS？

PSS, or Progressive Safe System[2], is a key component of DVS 2024. This system sets out seven requirements designed to enhance safety measures for low-star vehicles—those with limited direct vision—and to mitigate the risks posed to Vulnerable Road Users (VRUs), including cyclists, pedestrians, e-scooter riders, horse riders, and motorcyclists. By addressing the safety challenges related to drivers' visibility, PSS aims to prevent serious accidents and protect all road users.

PSS Overview

Figure 1: Schematic diagram of PSS 1-5 requirements

Image source: Direct Vision Standard - Guidance for operators [3]

Requirement 1: A Camera Monitoring System (CMS) must be fitted to the nearside of the vehicle, to eliminate the remaining blind spot at the nearside. A CMS can also be used as an alternative to fitting Class V and VI mirrors.

Requirement 2: Class V and VI mirrors, or a CMS that replaces the mirrors, or a combination of both, must be fitted to the front and nearside of the vehicle.

Requirement 3: A Blind Spot Information System (BSIS) must ensure full coverage down the nearside of the vehicle to detect vulnerable road users. It is clearly stated in the PSS BSIS technical specifications[4] that the number of false-positive activations due to the detection of static non-VRU objects in near proximity such as cones, traffic signs, hedges and parked cars shall be minimized. This aims to prevent left turn collisions.

Vehicles already approved to UNECE Regulation 151 are considered to have a BSIS likely to be more effective than one designed for this specification, and are therefore treated as compliant with this BSIS requirement.

Requirement 4: A Moving Off Information System (MOIS) must be fitted to the front of the vehicle, to warn the driver of the presence of a vulnerable road user and prevent collisions at the front blind spot zone when a vehicle moves off from rest.

Vehicles already approved to UNECE Regulation 159 are considered to have a MOIS likely to be more effective than one designed for this specification and are therefore treated as compliant with this MOIS requirement.

It is clearly stated in the PSS MOIS technical specifications[5] that the MOIS must be able to provide information and warning signals across at least the following areas: Lateral coverage area bounded by the nearside and offside vehicle planes (taken at the widest point,excluding mirrors,auxiliary equipment and super structures above the height of 2m from the ground plane), defined as d_w, plus nearside and offside separation planes (defined as d_NSP and d_OSP respectively) each extending 500mm laterally from vehicle side planes.

Figure 2: Areas diagram

The number of false-positive information signals due to the detection of non-VRU objects, such as other vehicles, shall be minimized. However, a warning signal is permitted if an imminent collision with a non-VRU object has been detected within the detection area as defined in the performance requirements section.

Requirement 5: Side under-run protection must be fitted to both sides of the vehicle, except where this would not be practicable.

Figure 3: Schematic diagram of PSS 6-7 requirements

Image source: Direct Vision Standard - Guidance for operators

Requirement 6: Audible warnings must be fitted to provide an adequate warning to road users when a vehicle is turning left (or turning right, for left-hand drive vehicles). This makes sure that compliant vehicles can warn of an intended manoeuvre.

Requirement 7: External warning signage must be displayed on vehicles to provide clear visual warning of the hazards around the vehicle.

Ultravision BSD System

Ultravision's Blind Spot Detection (BSD) system utilizes advanced machine vision and artificial intelligence algorithms to accurately identify vulnerable road users (VRUs), such as pedestrians and non-motorized vehicles, within the vehicle's blind spot. The system promptly alerts both drivers and pedestrians to help prevent traffic accidents caused by blind spots.

Figure 4: Ultravision BSD system diagram

Key features of the BSD system include:

● Right front BSD, right rear BSD, right side BSD

● Left front BSD, left rear BSD, left side BSD

● Alerts to remind drivers to be vigilant for pedestrians

● Notifications to pedestrians to keep a safe distance from vehicles

For more details, please visit the latest article about Ultravision BSD System: BSD - Blind Spot Detection System

Which vehicles need to install PSS?

All 0-star, 1-star and 2-star vehicles operating in London, including vehicles from outside of the UK. Some exempted vehicles are excluded, such as emergency service vehicles, military vehicles, etc. For details, please refer to: Direct Vision Standard and Safety Permit for HGVs[6]

Penalties and Grace Periods

If you drive an HGV in most areas of Greater London without a valid permit, you may receive a penalty charge (PCN) of up to £550 (reduced to £275 if paid within 14 days).

If you think you need more time to install the new safety measures required by the Progressive Safety System, you can apply for a grace period for a specific vehicle. The grace period will last for six months from 28 October 2024 to 4 May 2025, ending at 23:59. Getting a grace period is not automatic and requires you to apply for it. For more details, please refer to: Direct Vision Standard and HGV Safety Permit Scheme[1]

Summary

PSS is designed for aftermarket systems, enabling traditional fleets to obtain the HGV Safety Permit. In the London area, With 91% of low-star vehicles still in operation (data source: DVS - a world leading standard), the implementation of PSS represents an enhancement of DVS by TfL, tailored to the specific road conditions in London. Given that older vehicles cannot be replaced quickly, installing PSS is a wise choice for improving current road safety. As the P stands for, this is a gradual process.

Moreover, some performance requirements of PSS exceed those mandated by relevant UNECE regulations, reflecting the collision types observed in British practice. This highlights the need for policymakers to adopt safety regulations that are tailored to the unique road safety challenges in their respective countries or regions. PSS serves as a strong example of this approach.

The implementation of PSS will enhance road safety in London, further reducing serious injuries and fatalities caused by HGVs. We look forward to the latest data from TfL following the rollout of DVS PSS.

Written by Henry Chia on 2024.10.29

References

[1] Direct Vision Standard and HGV Safety Permit Scheme

[2] Progressive Safe System

[3] Direct Vision Standard - Guidance for operators

[4] PSS: Technical specifications for Blind Spot Information Systems

[5] PSS:Technical specifications for Moving Off Information Systems

[6] Direct Vision Standard and Safety Permit for HGVs