Three people have been killed in road crashes in Northern Ireland over the past 24 hours, police have said.
An 18-year-old man died after being hit by a vehicle while out walking in Co Armagh.
A PSNI spokeswoman said the accident happened on the Monaghan Road, Armagh, at about 4.30pm on Friday.
On Thursday night, a man and a woman were killed when their car hit a cattle lorry near Magherafelt, Co Londonderry. Police said the man had been driving the car and the woman was a passenger. They are believed to be members of the same family.
Two others were also hurt in the accident at Moneymore Road but their injuries were not believed to be life threatening. A spokeswoman for the PSNI said more details about the identities of those killed were not being released at the request of their family.
The Sinn Fein MLA said: "I'm sure they will be in the thoughts of many people. To lose two members of a family through a road traffic accident is always a tragic, sad occasion, it is especially more acutely felt at this time of year in the weeks before Christmas."
Four people have died in road accidents in his Mid Ulster constituency in recent weeks.
Mr McGuinness said: "We need to examine why this is the case and ensure that care is taken to ensure that we see no more dreadful occasions such as this."
The fatalities take to 43 the number of people killed on the roads in Northern Ireland so far this year, while 59 died in traffic accidents in 2011.