A man has been arrested following a collision on the A41 at the weekend.
Police are appealing for witnesses and information following the crash, which involved a cyclist and a Ford Transit van.
The incident occurred on the northbound carriageway, between the M25 junction and Hemel Hempstead, shortly after 12.20pm on Saturday (February 17).
The cyclist suffered serious injuries and was airlifted to hospital. The van driver was uninjured.
A 28-year-old man has been arrested in connection with the incident and is currently in police custody
Officers are appealing for anyone who witnessed the incident, or events leading up to it, to please contact the Bedfordshire, Cambridgeshire and Hertfordshire Road Policing Unit on the non-emergency number 101, quoting ISR 303 of February 17.