How long should I budget for transportation from Manhattan?

Help!! I'm chartering a bus to transport the guests from Manhattan to Long Island (De Seversky in Old Westbury). The ceremony starts 6.00pm on Friday.

When should I have the bus leaving? (4.30? 4?hospitality station starts 5.30pm)

I've driven the route before and it takes a bit more than half an hour but not at exactly that time and in a car (i suppose a bus would obviously be slower)... and all the traffic is making it hard to estimate!

Obviously my nightmare is everyone's an hour late or sth.. but if the bus gets there an hour early, it'll be bad too because there's nobody to greet the guests and we'll be taking photos so the guests cannot wander whereever they want on the grounds...

any suggestsions? thx thx

On a Friday it sometimes takes me an hour and a half just to get home (E. Side of NYC to the border of queens/Nassau). Sometimes shorter and sometimes A LOT longer. Avg is about an hour and a half though. And from me it's about a 35 min ride to Deseversky.

I'd get it from 3:30 just go play it safe.

Friday traffic is horrific.
My boyfriend would pick me up from work to take me to Commack some Fridays... it would sometimes take 2.5 to 3 hours!

yikes! we have the same situtation. our wedding is on a friday and we're going from manhattam to the crest hollow in the middle of rush hr! ughhh... im thinking its gonna take over an hr but (hopefully) under an hr and half...

Definitely do it at 3pm or 3:30pm. My fiance and I have had to go to rehearsal dinners and go for wedding meetings after work and when we leave at 5pm, we don't get to where we have to be until about 7p. The rush hour traffic is awful!!!
My dad used to be on the road a lot for work and he says that the rush hour traffic starts at about 4pm so definitely do it 3pm (to account for people that might be a little late).