THEORETICAL PEAK DAY

With all of the hassle of driving and parking at Disneyland, we should be grateful to those who had the foresight to make this less of a problem than it could have been. Van France, the creator of Disneyland University, said, "Today's visitor would have a difficult time visualizing what it was like. The Santa Ana Freeway was far from complete. There were still many signal lights. The local roads were all two lane. And, we were in the country. Sidewalks, curbings and gutters were to come later." 
One of the things we tend to forget these days was just how big the parking lot at Disneyland really was. At 102-acres, it was much bigger than the park it served. Was it simply a matter of taking the land not needed for the park and paving it over for the cars? No. Actually, like everything else at Disneyland, Walt and his team thought through what they we doing.
Keep in mind, in 1953 and 1954, there were very few attractions like Disneyland. The WED folks studied everything they could including Knott's Berry Farm, Forest Lawn Memorial Park, and the San Diego Zoo. Oddly, what they discovered was the crowds at Forest Lawn would ebb and flow just like visitors would at Disneyland in the early days.
Taking what they learned, the team began to make some basic assumptions. First, they conceded that 92% of the people visiting would arrive by car. At the venues they studied, they learned that each car averaged 3.7 persons. From there, they assumed that up to 43,500 guests would arrive by 9:00 a.m. and they would stick around until 1:00 p.m. And then leave. Then, another 43,500 guests would arrive after 1:00 p.m. And stay until sunset. This meant that the theoretical peak day would bring up to 87,000 guests. Take the number of guests and the number of cars necessary to bring those guests to the Park and they calculated that the parking lot would need to be at least 100 acres. 
This planning was done well before the management considered nighttime entertainment as part of the mix. Like Disney's Animal Kingdom in Florida, it was assumed that a visit to Disneyland would be primarily a daytime activity.