If you do a computerized light show they will come. If you get media coverage they will come in droves. It is in your best interest to keep the traffic under control. Very few neighbors ever have problems with the lights, the problem that will shut you down is traffic.
2010 was my first year doing a light show in Round Rock, TX and we had 5-10 cars at a time enjoying the lights. Then Bill O'Reilly aired our lights in his Pinhead vs. Patriot segment and suddenly we had a line of cars half a mile long coming out to see the lights. These are my notes as to what we did to manage the crowds. Again, it was only my first year so I'm sure others have more wisdom to add and there is good information in some of the sticky posts.
* Call the Police
In advance I called my local police department and let them know that we were expecting some traffic at our light show. Gave them my name and number so they could contact me quickly if there was an issue and at the same time I invited them to come by and enjoy the show. I ask for advice and tell them what I plan to do if there is a problem, turn the lights off for 10 minutes, let the crowds clear, start it up again, etc.
You can also hire off duty officers to manage traffic, but that can be expensive.
* Meet the Neighbors
Before the traffic show up I took a plate of cookies and a card to each of our nearby neighbors and if they had concerns about the lights we'd talk about them. It's good to know who might have a problem with the lights ahead of time. I asked them that if they had a problem to contact me.
This puts a face to the lights, gives them an avenue to address their problems. Being able to address problems directly with neighbors can avoid calls to the police or to the HOA. More often than not I found that neighbors were excited by the idea and ended with even more lights going up in the neighborhood.
* Signage
People need to know what radio station to tune to. Make sure that the print is big enough and lit so that people can see it. When our lines got long I found people would drive by, get the radio frequency, then drive back and get in line. Or they would hop out of their cars and run up to get the frequency number. This results in extra traffic. So on heavy traffic nights I made a sign on a paper plate with my frequency in big bold letters and put it 100-150 from the house.
If you have a website you can also post information about your lights there so people show to your show ready and informed.
* Getting Maximum view
When people park directly in front of the house only 2 cars can see at a time. So problem #1 was to get people not to park right in front of the house. I spoke to a few of the people and they were sweet as pie, just didn't realize they were blocking the view of others. When they blocked the view of others people would get testy, honking horns, yelling, etc. This is behavior that will anger the neighbors.
I looked around on some forums and found suggestions to do cones, but my wife said "Cones are not Christmas".
Instead I put out luminaires (bags with candles inside) in front of the house along the curb and this kept people from parking in front of the house. Not only did people not park in front of the house, but it enhanced the look of the place.
* Determine cars per hour. How many cars can see your show at one time?
I have a great situation where I have no across the street neighbors, a wide street, and neighbors who don't park in the road. Conservatively 6 cars can watch the show at once. Upto 10 can see, but not well enough that they don't sit through another cycle to see the full show.
Number_of_cars_per_hour = (60/Length_of_show ) * Number of Cars per show.
So if 6 cars watch the show at a time, and my show is 3 minutes long then
(60/3 min) * 6 cars per show = 120 cars/hour
If my show is 5 minutes long them
(60/5 min) * 6 cars per show = 72 cars/hour
* Multiple Versions of the Show
I came up with multiple versions of my show. I had the long version 15 minute long show that I would play during slower times. Then during heavy traffic I had a 6 minute, 5 minute, and 4 minute show. Worst case scenario was playing 1 song followed by a drop sequence. Not much of a show, but it kept traffic flowing. Even so, some people waited an hour to see the show.
We affectionately named the shows Defcon 1-4.
To make smooth transitions I didn't have any closing sequences, and the opening sequence was always a song. This way I could switch the show and make sure I never had two drop sequences in a row.
* Drop Sequence
At the end of each of the shows I used for the busy time I included a short drop sequence. This was a sequence where all the lights stay off. It was with a recording of myself or one of my girls reading a script. With the lights off it gave a chance for people that have seen the show to clear our and let the line advance. It also is an opportunity to lay down some best viewing tips with visitors. In my script I included....
Please be courteous to our neighbors
No parking or turning around in driveways
Stay to the far right so traffic can get by
Don't block roadways or intersections
No honking, yelling, or loud radios
Pull all the way forward
In this message we commented how nice our neighbors were and I think it went along way with our neighbors plus they knew we were doing our best to contain the crowds.
* Traffic Flow
Instructions you want to give for traffic flow will change depending on your situation. If possible setting up traffic so it flows one way will cut traffic by half. For example I could direct my visitors to leave the neighborhood by looping around vs. turning around and leaving the way they came. This cuts the traffic on the street down by half and lessens turnarounds in driveways and cul-de-sacs.
* Directing Traffic
I did this only a couple of times, but I really didn't enjoy it. The one thing it accomplished was I could get people to pull further forward increasing the number of cars that could watch each show. However; I really prefer providing an environment where it just works instead. Last thing I want to do at Christmas time was be heavy handed.
* Cleanup
This doesn't have as much to do with traffic as it does out of common courtesy for our neighbors. A couple times a week during the show I go out with a garbage bag and pick up any trash visitors might have left. Fast food wrappers, soda cans, gum wrappers, etc. My feeling was that the litter was my problem and my neighbors really shouldn't have to worry about it.
* Show Times
Online I posted show times, and put them in my drop sequence. That way everyone knew what time the show would end and I stuck to them. That way our neighbors knew when the show would end. On school nights I ran the show from 6-9PM. On non-school nights I ran the show through 10 PM, 10:30 PM around Christmas time.
On nights that I expected to be busy I would start the show an hour early to get more people through.
* Don't do a looping show
Instead of looping a show do 1 or two shows a night. I haven't tried this, but have spoken to people to have. While it may get rid of the car traffic, you might have people camping out hours in advance of the hundreds that eventually show up for the show.
* Weekend shows
Another option is to try reduce your shows to just running on the weekends. I tried this, it didn't work. It just made the weekends just that much worse. Running the show on the weeknights was a release valve of sorts of traffic that happened over the weekend.
* Randomizing show times
Don't run your show to a published schedule. Kick off a short show every so often. This did work for me, but there were a few people that would just camp out and wait until the next show. If this became too much it would've become a problem.
* Switch to a sit down show
Instead of doing the typical looping show one option is to throttle it back just to family, friends and neighbors. Block off the street in front of the house ("block party"), have everyone bring out their camp chairs. Everyone, including you, gets to enjoy the full show plus enjoy the interaction. I have done this for a couple years and really enjoy it. You aren't sharing the show with thousands, but a few dozen, but it is a much more neighborly event.