Police are appealing for information, witnesses and dashcam footage following the incident at around 6.15pm on Saturday, March 26.
Two motorists, a man and woman, were involved in an altercation at the bottom of Midland Road, which continued onto Queensway and St Pauls Road – causing a build-up of traffic in their wake.
The man and woman got out of their vehicles and police received reports that man, who was driving a white Vauxhall Corsa, threatened and pushed the woman, and called her a racist slur.
PC C-Jay Callaghan, who is investigating, said: “A 22 year old man from Hemel Hempstead has been arrested on suspicion of a public order offence, assault and criminal damage.
"He was bailed until 27 March and has now been released under investigation.
“We are carrying out further enquiries and are keen to hear from anyone who might be able to help. We understand the incident led to a build-up of traffic so we are hopeful that there are many witnesses.
“If you saw any of what happened or have information, please get in touch. If you were driving in the area at the time and have a dashcam fitted to your vehicle, please check it and get in touch if you spot something that could help the investigation. You can get in touch by calling the non-emergency number 101 or email me at [email protected] quoting crime reference 41/24136/22.”
A police spokesman added: “Hertfordshire Constabulary does not tolerate racism and reports of this nature are taken extremely seriously. You can visit hertsagainsthate.org for support around hate crimes and hate incidents.”