A man driving near a Berkshire park swerved to avoid a deer and hit a tree at 50mph this week.
He was cut out of his car by firefighters and taken to hospital by ambulance to be treated for head and chest injuries.
Station manager Adam Stevens, from Langley fire station, warned drivers to be careful at this time of year as wildlife are increasingly coming into urban areas.
"With spring you've got the wildlife out there, desperately looking for food to feed their young," he said.
"A small deer, muntjac probably, came out in front of the driver, who was travelling along at 50mph near Black Park in Langley, he saw the animal, swerved and hit a tree."
According to Mr Stevens and the Deer Initiative , a group of charities and government agencies which aims to control deer numbers, more accidents will follow over the coming weeks.
May is when young deer begin dispersing and looking for new territories as the breeding season begins.
"The peak month in which you see deer on the roads is during May, and this is when there is the overall peak of deer accidents," said Jochen Langbein, of the Deer Initiative.
"There is another peak in autumn, which is when red and fallow deer, our biggest species, are fighting and mating, which can cause accidents.
"But the smaller roe and muntjac deer which make up the bulk of our deer population tend to be most active during the spring."
Mr Langbein has been involved in researching deer populations and numbers of correlated road accidents for over a decade, and says in that time the numbers of deer in England have more than doubled.
The deer population is now in the region of 1.5 million.
The reasons for the increase range from mild winters, the drive to re-introduce woodland to the UK to a fall off in the number of deer culled every year.
To keep populations stable, 300,000 need to be culled every year, but only 200,000 are being culled annually at present.
In total, the UK is home to six species. Of these, 100,000 to 200,000 are muntjac deer, a Chinese species introduced to England a century ago and prevalent in urban areas of south and south eastern England. Sika and Chinese water deer arrived in the UK at the same time.
Fallow deer, which came across in the Norman conquest 1,000 years ago, now have a population between 100,000 to 200,000.
However, the native roe deer is still the most common, numbering 800,000 animals in total, and native red deer, which number 350,000, remain the largest land mammals in the UK, though they are mainly found in Scotland.
The animals could be responsible for as many as 74,000 car accidents in the UK each year, according to a report released last year by the Deer Initiative.
Mr Langbein said areas such as Oxfordshire, Berkshire and Hampshire and the home counties had particularly large deer populations, combined with ever-increasing traffic on rural roads.
He said the highest number of deer-related traffic accidents was in Hampshire and the home counties.
He added that it was difficult to predict exact numbers, as such data was not recorded nationally, but estimates say in excess of 50,000 deer are hit every year as well as 500 human injury accidents.