 In April 1989, a Greyhound Lines bus with 11 passengers on board travelling to New York City from Montreal was hijacked by an armed man and driven onto the lawn in front of the Centre Block.A standoff with police ensued and lasted eight hours; though three shots were fired, there were no injuries.After a second incident in September 1996 where an individual forcibly drove his car into the Centre Block doors and proceeded to attack RCMP officers standing guard, it was decided in the interests of national security that Parliament Hill, which up to that time had been open to limited public traffic on the lower lawn, would be restricted to government and media vehicles only.