Why situational awareness saves lives: what a traffic jam can tell you

The moment a dispatch call comes in, a HEMS crew begins building a mental picture of a scene they have never seen. Every scrap of information matters: the nature of the incident, the location, the weather, the terrain. But one of the most reliable and underrated signals is already visible from the cockpit long before the landing site comes into view: the traffic below.

What situational awareness actually means

Situational awareness is not simply paying attention. The concept was formalised by researcher Mica Endsley in a model that breaks it into three levels: perception of the elements in the environment, comprehension of what those elements mean together, and projection of how the situation will develop in the near future. All three levels are required before a crew can act with confidence.

In aviation and emergency medicine, this framework has become foundational. As the trade publication AirMed and Rescue describes it: HEMS and search and rescue pilots operate in a fast moving, fast changing environment in which good all-round visibility and an ability to act decisively on large amounts of complex data are essential. A crew that loses situational awareness does not simply make a worse decision. It often makes no decision at all, or the wrong one, at the worst possible moment.

Emergency medical dispatchers face the same challenge on the ground. Research published in the International Journal of Human-Computer Studies found that senior operators in emergency dispatch centres develop an ongoing mental picture of their operational area that shapes every triage decision. When that mental picture is incomplete or out of date, response quality suffers in ways that are difficult to trace back to a single cause.

Traffic jams are not just an obstacle

Most people think of road traffic as something emergency services have to fight through to reach a scene. That framing is correct, but it misses something important. A traffic jam is also a signal. It tells you where something has happened, often before any other information is available.

The US Federal Highway Administration estimates that more than 50 percent of all urban freeway congestion is incident related. A crash, a medical emergency on the carriageway, a vehicle fire: all of them collapse the surrounding traffic network into a distinctive shape. Research published on ResearchGate found that around 12 percent of urban freeway incidents trigger rubbernecking queues in the opposite direction, with those queues extending on average more than two miles from the incident location. Capacity on uninvolved lanes drops by up to 50 percent as drivers slow to look.

From altitude, that congestion pattern is readable. A sudden pinch point in otherwise free-flowing traffic is not random. It points to something, and experienced HEMS crews know it. SKYbrary, the safety knowledge base maintained by EASA and Eurocontrol, notes that HEMS accidents occur more frequently on approach to a patient than at any other phase of flight, partly because crews must locate scenes with limited pre-positioned information. Ground cues, including the pattern of stopped or slowing vehicles, emergency vehicle lights, and gathering bystanders, are among the primary tools crews use to confirm they are approaching the right location.

Crowdsourced traffic data detects incidents before official reports

The relationship between traffic anomalies and incidents has been studied quantitatively. A peer reviewed study published on arXiv found that 27.5 percent of incidents in official traffic authority databases were detected earlier by Waze than by the authorities themselves. Only 43 percent of real incidents appeared in both the Waze data and the official logs, meaning a large proportion of real world events show up as traffic anomalies in GPS data before they are formally registered anywhere.

This matters for emergency response. A live traffic layer showing an unexpected queue on a rural road at 2am is not noise. It is information. It tells a dispatcher or an airborne crew that something has changed at that location in the last few minutes, even if no caller has yet provided a precise address.

The cost of getting there late

Situational awareness is not an abstract concept. It has a direct effect on survival. Research in emergency medicine has consistently shown that for cardiac arrest, every minute of delay reduces the probability of survival by seven to ten percent. Traffic congestion adds on average nearly ten minutes to ambulance response times in congested urban areas. In New York City, average ambulance response times rose from under twelve minutes to over thirteen minutes in a single year, with heavy traffic cited as a primary cause.

HEMS aircraft avoid most of those delays by flying above the road network, but they are not immune. Finding the scene quickly, setting down in the right place, and leaving a clear path for ground ambulances all depend on the crew understanding the situation around them before they land. A ten second improvement in locating the exact scene can translate directly into time saved on the clock that is always running.

Seeing the picture before you arrive

The role of a HEMS technical crewmember, as described in operator documentation from services such as MAGPAS, explicitly includes maintaining situational awareness on approach: assessing landing sites, obstacles, and access routes while still airborne. The traffic pattern around a scene is part of that assessment, not an afterthought.

What changes when a crew has access to a live traffic layer on their device is the quality of the picture they can build before they even enter the area. Instead of searching for a stopped queue from a thousand feet, they can see it charted on a map, overlaid with the aircraft position, several minutes out. That is the difference between level one situational awareness, perceiving raw data, and level three, projecting what the scene will look like on arrival and planning accordingly.

Live traffic in AirAssist

The live traffic layer in AirAssist Pro overlays real time road conditions on the same map that shows aircraft positions, routes, and incident data. For a HEMS professional, that means a single screen that combines the aerial picture with the ground picture. A backup on the A2 that was not there ten minutes ago is not irrelevant background noise. It is a possible scene marker, and it is visible before the call has finished.

Situational awareness degrades the moment information stops flowing. A map that shows aircraft but not the ground conditions around them is half a picture. Combining both is not a convenience feature. For the professionals who rely on it, it is the difference between arriving prepared and arriving to figure things out.