The A41 was closed on Saturday after icy conditions caused a five car smash on the busy bypass.
Police, fire and ambulance crews were called to the carriageway close to the Hemel Hempstead slip road just before 8am and highways gritters were alerted.
One person was taken to hospital.
The road remained closed until 1pm, causing gridlock around parts of Hemel Hempstead.
On the same day, just before 9am, there was another accident near Bourne End, heading towards Aylesbury.
This involved just one car, which had to be recovered, and no-one was injured.
It is not the first time that the bypass has been closed due to icy conditions. Police shut the road as a precaution in December last year after a series of accidents.
Councillor Terry Douris, who oversees highways, said: “Due of the nature of this road we routinely treat with it with extra salt. The A41 is one of the precautionary routes - i.e. it is treated pre-freezing - and it is treated using extra salt. Gritting teams will then re-visit the route with a further salting should the weather and/or road temperature forecast indicate it is necessary or, as was the case on Saturday, by request from the police or emergency services. We carried out two additional runs at the weekend on the A41, one on Saturday and another on Sunday evening.
“However, gritting can never guarantee that a road surface will remain entirely ice free. Salt is the best material we have available to treat snow and ice, but drivers still need to be careful and should not drive as if weather conditions are normal. Leave plenty of room between you and the vehicle in front, steer and brake very gently and reduce your overall speed. Please also allow extra time for any journeys you make.”
There is more information about Herts County Council’s winter service and driving tips at www.hertsdirect.org/salting and drivers can find out when roads are being gritted as it happens via Twitter at twitter.com/herts_highways
There’s also a severe weather section on the council’s website www.hertsdirect.org/winter