The glimmer on the asphalt, the brake that doesn't respond, then the roar: how 80 vehicles crashed in the tunnel on the A20

The scene, motorists recount, began with a pungent smell and an unusual shimmer on the asphalt: just touching the brake was enough to feel the vehicle lighten, sliding as if on soap. In an instant, the morning routine of commuters using the A20 highway was disrupted: at 8:30, in the tunnel, the first chain collision, followed by others, in succession. According to the information gathered, a suspected fuel leak from a heavy vehicle made the surface extremely slippery. The dynamics are still under investigation, but initial interventions have confirmed the situation: contaminated pavement, good visibility, and normal weather conditions. The result, however, was severe: a massive involvement of vehicles - about 80 according to estimates - and a traffic jam that paralyzed the Messina-Palermo highway for hours. Fortunately, there are currently no serious injuries.

What has been reopened and what has not

The Rometta entrance ramp towards Messina has been reopened: motorists coming from the Tyrrhenian coast can now re-enter the highway and reach the capital. This measure aims to absorb the queues on the SS113 and on the municipal roads that formed as a result of the blockages. The reopening of the entrance towards Messina was decided after safety checks on the stretch of roadway not affected by the spilled substance and after cleaning and restoration operations in the most critical sector. In the recent past, in the presence of exceptional events (such as the fire in the Telegrafo tunnel in the Messina area, which blocked access), the authorities have already adopted similar solutions to modulate flows and alleviate the most congested nodes.

Meanwhile, the section towards Palermo in the segment closest to the area of the accidents remains closed: here, the Traffic Police are still conducting investigations, cleaning the pavement, and checking emergency equipment in the tunnel. In similar cases, operators mandate mandatory exits at previous interchanges and re-entry at subsequent ones, with detours along the SS113; this same logic has been applied multiple times along the Messina–Rometta–Milazzo axis during extraordinary closures for construction sites or accident events.

Why here: the "sensitive" section

The Messina–Villafranca–Rometta–Milazzo corridor is one of the most delicate sections of the A20: the presence of numerous tunnels, high traffic volumes entering and exiting the metropolitan area of Messina, cyclical maintenance work, and an alternative route (the SS113) that cannot fully absorb sudden peaks. It is no coincidence that in recent years there have been recorded accidents and critical issues, some resulting in temporary closures and detours. What matters today is that the incident on March 17, 2026 has reignited the spotlight on the need for constant maintenance of the tunnel infrastructure and on traffic management plans that are more resilient to shocks, especially when an unexpected event – such as a spill of diesel – disrupts the entire system.

The dynamics: the invisible trail that multiplies impacts

According to an initial reconstruction, the trigger was the fuel leak – most likely diesel – from a heavy vehicle that had passed shortly before. This is a well-known phenomenon to traffic technicians: a few dozen liters spilled, especially in tunnels or on curves and ramps, can drastically reduce grip and turn even a light braking into an unexpected extension of stopping distances. The Sicilian case studies, and not only, show that spills in tunnels are among the most critical contexts because they occur in a confined environment, with limited maneuvering margins and optical reflections that can delay the perception of danger. Recent episodes on other arteries of the Island (such as the major pile-up in the tunnel on the A19 at Trabia) confirm the pattern: a trail of fluid on the asphalt, chain collisions, roadway closed for restoration.

This morning's trigger occurred during peak hours: the wave of slowdowns became a compact column, and inside the tunnel, the margin for error was eliminated. From that moment, standard protocols were activated: danger notification, closure of the section, activation of ventilation and emergency traffic lights where available, and a call to clean-up teams. In similar scenarios, the technological systems recently activated in the Messina network have shown they can accelerate safety procedures, interrupting flows and facilitating the arrival of rescue teams.

The open questions

The exact origin of the spill (the loss of diesel from a heavy vehicle  is the favored hypothesis but there are no confirmations), the timeline of the initial collisions (which vehicles triggered the chain collision and at what speed were they traveling?) and the effectiveness of the signage approaching the tunnel (variable message signs, speed limits, and warnings were they active and visible?). 

Answers will come from the investigations of the Traffic Police and the technical checks of the CAS; only after these activities will it be possible to estimate realistic times for complete reopening. In the immediate future, a phased reactivation is expected, with the first windows reserved for emergency vehicles and subsequent assisted flow of vehicles remaining downstream of the incident.

The voice of users and the resilience of the system

The images circulated on social media and the phone testimonies collected along the SS113 depict a morning of great frustration: missed appointments, delayed goods, diverted buses. It is the flip side of a network that, in the Tyrrhenian quadrant, has few emergency corridors: when the A20 stops, the coast becomes saturated. Not surprisingly, in previous traffic crises, local media have emphasized the need for diversion routes and more effective real-time updates, both on official channels and on variable message signs.

What to expect in the coming hours

Once the cleanup and investigations are completed, the operator will be able to proceed with a progressive reopening also towards Palermo, initially with speed limits and construction signage. If the investigations confirm the fuel leak as the primary cause, attention will shift to the conditions of the heavy vehicle and the chain of responsibility, including the possibility of charging the restoration costs and ancillary damages to traffic and the community. For users, in the next 24–48 hours, a “accordion” effect may persist on the ramps and the nearest exits: consulting the CAS channels and local media before traveling remains the golden rule.