Every HGV has four defined blind zones — nearside, offside, front nearside, and rear. Construction vehicles have these plus additional blind zones created by specialist bodies: the underside of a raised tipping body, the extended drum profile of a concrete mixer, the lateral sweep zone of a tipper grab arm. They also operate in environments where the people most likely to be in those blind zones — banksmen, site workers on foot, plant operators — are present throughout the working day. Blind-spot prevention on construction vehicles is not a generic HGV compliance exercise. It requires a camera and sensor configuration that accounts for both the vehicle body and the operating environment.
The four blind zones on a standard HGV are: the nearside, where a cyclist or pedestrian alongside the vehicle cannot be seen in the driver’s mirror; the offside, which has a smaller but genuine blind area at the side and rear of the cab; the front nearside, where a pedestrian or cyclist directly in front of the vehicle cannot be seen below the cab sightline; and the rear, where the driver has no direct vision behind the body.
HGVs account for a disproportionate share of cyclist fatalities in the UK — consistently around 17-18% of cyclist deaths from vehicles that represent less than 4% of non-motorway traffic. The nearside is the most common impact point in HGV-cyclist collisions: 41% of contacts occur on the left side of the vehicle. The front is the most common zone in HGV-pedestrian collisions. These statistics reflect the geometry of the blind zones, not the behaviour of individual drivers.
FORS Silver v7 and CLOCS v5 address these zones with camera and sensor requirements — nearside BSIS detection, rear camera, and left-turn warning, with MOIS front detection recommended as a matter of course. These are the baseline. For construction vehicles, additional body-specific blind zones require additional coverage.
Tipper lorries create a rear underside blind zone when the body is raised. The hydraulic rams and chassis become visible, and the space underneath and behind the raised body creates a zone where a site worker or plant operator cannot be seen from the cab. A chassis-mounted rear camera provides a consistent view of the rear of the vehicle regardless of body position — a body-mounted camera has no useful view when the body is raised. The nearside alongside the tipper body, particularly the gap between the cab and the body on chassis-extended tippers, is also a blind zone that standard mirror positions do not fully resolve.
Concrete mixers have a rotating drum body that extends rearward and outward beyond the standard HGV profile. The drum creates an offside rear blind zone that is larger than on a standard curtainsider or box van body of the same overall length. Rear proximity sensors mounted on the chassis rear face may not detect objects adjacent to the drum body. The rear camera needs to account for the drum’s extended profile in its field of view — a camera positioned too narrowly will show the drum but miss the zone alongside it.
Tipper grabs add an overhead blind zone during grab arm operation. The arm sweep zone extends above and alongside the vehicle — a zone that no standard mirror or camera position covers. Sensors and cameras on the grab arm mechanism itself, or a wide-angle cab-roof camera covering the overhead arc, are the appropriate coverage for this vehicle-specific blind zone.
The Blind Spot Information System (BSIS) requirement — mandatory in DVS Progressive Safe System configurations for HGVs over 12 tonnes in Greater London — detects vulnerable road users in the nearside blind zone while the vehicle is moving at speeds up to 30km/h. For construction vehicles operating on approach to and departure from CLOCS sites in London, BSIS compliance is both a DVS legal requirement and a CLOCS/FORS Silver condition.
A point that comes up consistently in construction fleet specification discussions is whether existing ultrasonic proximity sensors satisfy BSIS requirements. They do not. DVS 2024 BSIS specifications require the system to distinguish moving VRUs from stationary objects — a capability that standard ultrasonic sensors do not have. Radar or camera-based BSIS that meets the DVS 2024 specification is the appropriate system for construction vehicles over 12 tonnes operating in London.
Outside London, BSIS is not a DVS legal requirement, but it satisfies the FORS Silver nearside proximity sensor requirement and represents the appropriate standard for construction vehicles operating at CLOCS-adopting sites where banksmen and site workers are in the nearside zone throughout the working day.
The Moving Off Information System (MOIS) — not mandatory under FORS Silver, but recommended as a matter of course — detects cyclists and pedestrians in the front nearside zone when the vehicle moves off from a stop. For construction vehicles, which stop repeatedly at site gates, weighbridges, fuel points, and delivery positions, the MOIS scenario occurs far more frequently than for a road freight vehicle that stops only at delivery bays.
A banksman positioned in front of the vehicle to give departure clearance, or a site worker crossing in front of the vehicle at a queue position, is exactly the type of hazard MOIS is designed to detect. Construction site environments produce the specific scenario that MOIS addresses — a pedestrian in the front nearside zone at the moment of departure — on every shift, multiple times per vehicle.
MOIS sensors on construction vehicles should be configured to be active only during the stationary-to-moving transition and at low speeds. At road speed, a MOIS alert that triggers from oncoming traffic or roadside infrastructure generates false alerts that degrade driver responsiveness. The FORS v7 false alert compliance definition — sensors that trigger from the vehicle’s environment rather than genuine VRU hazards are non-compliant — applies to MOIS as to all other sensor types.
Camera coverage fills the gaps that sensors cannot address. A BSIS sensor alerts when a VRU is present; it does not show the driver where the VRU is or what they are doing. A nearside camera with in-cab display provides the visual context that allows the driver to make an informed decision — whether the person alongside is moving into the vehicle’s path, or is stationary behind the hazard zone. Both the sensor alert and the camera view are required; neither is sufficient alone.
For construction vehicles, the camera positions that address body-specific blind zones are: a chassis-mounted rear camera covering the area behind the vehicle at all body positions; a nearside kerb-level camera at the rear nearside corner covering the crew-on-foot zone; and, for tipper grabs, an arm-mounted camera showing the claw zone during grab operations. These positions supplement the standard five-camera configuration without replacing it.
Yes. Standard HGVs have four defined blind zones — nearside, offside, front nearside, and rear. Construction vehicles add body-specific zones: the underside of a raised tipper body, the extended drum profile on a concrete mixer, and the grab arm sweep zone on a tipper grab. These additional zones require camera and sensor coverage beyond the standard HGV configuration.
Yes. Any HGV over 12 tonnes operating in Greater London requires BSIS as part of the DVS Progressive Safe System — including tippers, concrete mixers, and tipper grabs. Standard ultrasonic sensors do not satisfy DVS 2024 BSIS requirements. Radar or camera-based BSIS that distinguishes moving VRUs from stationary objects is the required specification.
MOIS is not mandatory at FORS Silver, but fitting it as a matter of course is recommended for vehicles over 7.5 tonnes — including construction vehicles accessing CLOCS-adopting sites. Construction vehicles stop repeatedly at site gates, weighbridges, and delivery positions throughout the working day, making the MOIS scenario (pedestrian in front nearside zone at departure) a frequent occurrence on every shift.
The drum extends the mixer’s offside rear profile beyond the standard HGV body width and length. Rear proximity sensors mounted flush on the chassis rear face may not detect objects alongside the drum body. The rear camera field of view should account for the drum’s extended profile — a narrowly positioned camera shows the drum but misses the zone adjacent to it during reversing.
Yes. BSIS-compliant radar or camera sensors can be retrofitted to most construction vehicle configurations. The existing wiring and MDVR may need to be assessed for compatibility — BSIS systems typically integrate with the in-cab display and, on DVS PSS configurations, with the audible warning system. A site survey by the installer before retrofit confirms the mounting positions and integration requirements for each vehicle body type.
A printable checklist covering standard HGV blind zones, tipper and mixer body-specific zones, tipper grab arm coverage, BSIS and MOIS calibration, and FORS Silver v7 / CLOCS v5 compliance for construction vehicles.
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Related guides: Live View for Construction Sites · Sensor Systems Required for Construction Fleets
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