How Many Cameras Does a Truck, Bus or Van Need?

A van, a taxi or a car needs two cameras: one on the road and one on the cabin. A truck needs three or four, adding the nearside blind spot and the rear. A bus needs four to eight, to cover the driver, each door, the aisle and the rear. The number comes from the views you would want after an incident, not from the size of the recorder.

Start with the views

List the questions a claim or a complaint would raise, and give each one a camera:

1. What happened ahead? A road-facing camera. Every vehicle needs this one.
2. What was the driver doing? A cabin camera, ideally infrared, which also allows driver monitoring.
3. What was alongside? A side camera on the blind-spot side of long or tall vehicles.
4. What was behind? A rear camera, for reversing incidents and rear-end collisions.
5. What happened on board? Door and aisle cameras on passenger vehicles; a cargo camera on delivery vehicles.

By vehicle type

Two cameras: road and cabin

For taxis, ride-hailing cars and vans, a dual-lens dashcam covers the road and the cabin. The D9 records both in 1080p, with an infrared cabin lens and ADAS and DMS alerts. Where the rear matters more than the cabin, the A5 records the road in 2K and the rear in 720p.

Three or four cameras: trucks

A truck adds the two places its driver cannot see: the nearside and the rear. There are two ways to reach four channels:

• A dashcam with extra cameras. The D9 and the WD02 have two built-in lenses and take two external 720p cameras. Apart from power, the only cabling is to those two cameras, and the D9 ships with one rear camera on a 5-metre cable.
• A four-channel MDVR. The WD12 records four 1080p inputs. Blind-spot detection through a BSD camera is an option on it.

Four to eight cameras: buses

Passenger vehicles need the driver, the doors and the aisle as well as the road. The WD10 takes four 1080p or eight 720p cameras and a hard disk of up to 2 TB. It can count passengers on one to four doors, but not while ADAS and DMS run, and each counter uses two channels. The WD11 takes the same number of cameras, records to two SD cards of up to 256 GB each and counts with 3D binocular sensors.

Check storage before you add cameras

Each 1080p camera records about 1.8 GB an hour at our standard bitrate of 4 Mbps, so four cameras use about 7.2 GB an hour, and a 256 GB card holds about 33 hours of four-camera video. Recording the side and rear cameras at 720p brings that down to about 6.3 GB an hour. Work out your own setup in the storage calculator.

If you are still deciding between a windscreen unit and a recorder, see dashcam vs MDVR.