Construction sites with computer vision: PPE, danger zones and equipment performance
How construction companies use AI cameras to check helmets and vests, keep people away from cranes and excavators, and measure how many hours every machine works, idles or sits parked.
The limits of walk-around inspections
A safety officer on a large site cannot be everywhere. Inspections happen a few times a day, workers know when the officer is near, and the riskiest moments, such as a lift, a reversing truck or a late shift, often happen when nobody is watching.
Computer vision does not replace the safety officer. It gives them eyes on every camera, all shift long, and a list of the moments that need their attention.
What the cameras check
- Helmets, high-visibility vests, gloves and harnesses, per zone and per shift.
- People inside the swing radius of excavators or under a crane load.
- Unauthorised entry to excavations, roof edges and electrical rooms.
- Blocked emergency routes and material stacked in walkways.
- Smoking in no-smoking areas and early signs of smoke or fire.
- Equipment working hours and idle time for each machine.
Equipment performance: what each machine is really doing
Heavy equipment is one of the biggest costs on a site, whether it is owned or rented by the day. Yet most project teams only know how many hours a machine was on site, not how many hours it actually worked. The same cameras that watch safety can answer that question for every excavator, loader, crane, dump truck and concrete pump.
| State | How the camera sees it | What it tells you |
|---|---|---|
| Working | The arm, bucket or boom is moving, or the machine is travelling and loading. | Productive hours you are paying for. |
| Idle | The machine is in position but not moving, often with the engine running. | Waiting for trucks, materials, instructions or an operator. |
| Off or parked | The machine stays in the yard or parking zone. | Equipment that may not be needed on this site. |
| Out of hours | Movement outside the approved shift. | Unauthorised use, fuel loss or security issues. |
- Working, idle and off hours for every machine, per shift and per day.
- Utilization: the share of on-site time each machine is actually working.
- Long idle periods with the engine on, which burn fuel for nothing.
- The first and last movement of the day, compared with shift times.
- Which zone each machine worked in, so progress can be linked to activity.
- Trucks loaded per hour by each excavator or loader, and how long trucks wait to be loaded.
- 01Return what you do not use
Rented machines with low utilization for days are the first candidates to send back.
- 02Fix the real bottleneck
An excavator idle while waiting for trucks points to a haulage problem, not an excavator problem.
- 03Plan maintenance on real hours
Service intervals based on actual working hours, not calendar days.
- 04Check subcontractor invoices
Compare billed machine hours with the hours the cameras recorded.
From alerts to a safety culture
The most valuable output is often the daily report, not the single alert. When compliance is measured by zone, contractor and shift, site managers can see where the problem really is: a specific subcontractor, the night shift, or one gate where workers remove their helmets.
- 01Week 1
Measure the baseline quietly, without alerts, to understand normal behaviour.
- 02Weeks 2–4
Turn on alerts for the top risks and share the daily compliance report with supervisors.
- 03Month 2 onward
Use trends by contractor and zone in toolbox talks and contractor reviews.
Practical tips for camera placement
- Cover gates and access points first: everyone passes through them.
- For PPE, workers should appear large enough in the frame; a wide view of the whole site is better for zones and vehicles.
- Sites change every week. Review zones whenever the layout or crane position changes.
- Solar or 4G cameras can cover areas without power or network.
Questions we often hear
Can AI detect PPE at night?
Yes, with adequate site lighting or infrared cameras. High-visibility vests are usually easier to detect at night than helmets, so test both on your footage.
Can cameras track equipment that has no telematics?
Yes. Utilization is measured from what the machine is visibly doing, so it works for owned, rented and subcontractor equipment alike, with no device installed on the machine.
Does it identify individual workers?
Not by default. PPE and zone rules work on anonymous detections. Identification only happens if you add face recognition for attendance, with proper consent.