When the Cause Isn’t Clear: Understanding Defences in Dangerous Driving Cases

A recent Fleet News article highlighted the case of Kuljinder Singh, a professional HGV driver sentenced to almost four years in prison for causing serious injury by dangerous driving after colliding with queuing traffic on the A27 near Chichester.

Police described it as a “miracle no one was killed”;  but what stood out was what wasn’t said. Phone use was ruled out. There was no evidence of alcohol or drugs. Yet the court still found his driving “fell far below the standard of a competent driver.”

For anyone behind the wheel of a commercial vehicle, this kind of case is deeply unsettling. When the common explanations are ruled out, the question becomes: what else can make otherwise competent driving dangerous?  Every collision has its own dynamic, and whether the driving is deemed to be “dangerous” or “careless” will depend on detailed analysis of the evidence.

Human Factors: Perception and Reaction Time

One of the most important considerations in any collision is how quickly a driver could perceive a hazard and react to it. Even the most careful driver needs a fraction of a second to process what they see before taking action.

Studies show that average perception–reaction times range between 1.5 and 2.5 seconds, depending on the circumstances. In that brief moment, a car travelling at motorway speed can cover the length of a football pitch. If an unexpected hazard appears such as a pedestrian stepping out, an animal crossing, or a stationary vehicle without lights, it may simply be impossible to stop in time, even if the driver’s observation was adequate.

Expert analysis of driver perception–reaction time is often central to establishing whether the driving truly fell below the expected standard. It can help demonstrate that, while a collision occurred, it was unavoidable in human terms.

The Looming Threshold

Another critical concept is the looming threshold - the point at which an approaching object grows large enough in a driver’s field of vision to be consciously detected as a hazard.

To put it simply: have you ever driven along a long, straight road and suddenly realised that the car ahead, which seemed to be miles away, is now right in front of you? That is the looming effect. Our brains rely on the apparent size and rate of expansion of an object to gauge distance and closing speed. In poor light, at high speeds, or when the approaching object offers limited contrast (for example, a dark vehicle against a dark background), the object may not reach the looming threshold until it is dangerously close.

In court, understanding and explaining physiological limitations such as these can be vital. Expert evidence in these areas can demonstrate that what might appear in hindsight to be an obvious hazard, may not have been perceptible to the driver until the very last moment.

Unexpected Hazards and External Factors

Not every collision is the result of culpable driving. Unforeseen hazards - animals, mechanical failures, pedestrians in dark clothing, stationary vehicles without lights, or debris on the carriageway  - can present dangers that no reasonable driver could avoid. Establishing these circumstances can be pivotal in rebutting the suggestion that the driving was below or far below the expected standard.

Medical Issues

Where loss of control arises from a sudden medical episode (such as an undiagnosed seizure or cardiac event) the issue of foreseeability becomes key. If the driver had no prior warning of the condition, criminal liability may not follow.

Procedural and Evidential Challenges

Early legal engagement is vital. Cases often turn on forensic collision investigation and the interpretation of physical and digital evidence. Early dialogue with the police and CPS may allow the defence to:

• identify inconsistencies in the prosecution’s expert evidence,

• instruct independent experts to re-examine data and scene evidence, and

• challenge assumptions or findings on speed, sightlines, and reaction opportunities.

Negotiating with the Prosecution

Where the evidence supports a lesser finding of culpability, it may be possible to negotiate with the prosecution to accept a plea to the lower offence of Causing Death or Serious Injury by Careless Driving rather than dangerous driving. This requires detailed written defence representations, supported by expert opinion, and a deep understanding of prosecutorial discretion and public interest factors. The outcome can mean the difference between a custodial and a non-custodial sentence.

Sentencing Overview

Sentencing for these offences reflects the harm caused and the level of culpability found.

For causing death by dangerous driving, the maximum sentence is life imprisonment, with a mandatory disqualification from driving for a minimum of five years and a compulsory extended re-test before a licence can be regained. For causing death by careless driving, the maximum sentence is five years’ imprisonment with a mandatory disqualification of at least twelve months.

In both offences, the court will assess culpability and harm in accordance with the Sentencing Council Guidelines, taking into account factors such as the degree of danger created, the driver’s level of awareness and any aggravating features (for example, excessive speed, distraction, or impairment) The driver’s remorse, previous good character, and cooperation with the investigation may be considered in mitigation.

The Importance of Specialist Representation

Investigations into fatal road traffic incidents are highly technical, evidence-heavy, and emotionally charged. Drivers are often interviewed under caution whilst still in shock and before they fully understand the implications of what has occurred. Early, specialist representation can make a decisive difference. 

If you or someone you represent is under investigation for a serious driving offence, contact LMP Legal - specialist road traffic lawyers with national expertise in defending fatal and serious collision cases.