When I visited (five years ago or so), boats were at least an order of magnitude less common in Venice's canals than cars are on the roads of a typical city, perhaps two or three orders of magnitude. It's far from a technicality.
http://www.italymag.co.uk/italy/venice/canal-traffic-getting... - "Venice may have no cars but it has plenty of boats and their number has been on the increase over the past years. So much so that the usually tranquil canals of Venice now at times resemble the more chaotic traffic of Rome or Milan."
I counted about 500 boats on the Grand Canal using Google's map imagery, either in motion or moored. (From the train station to Piazza San Marco.) The distance is ~3km. How do you map that to car traffic? Boats carry more than cars and a vaporetti caries more than a bus. After all, the boats carry a good fraction of the 18 million tourists per year.
Boats also need more space and go at different speeds. Did you factor in wake pollution? Quoting the quite work from WPI (http://www.wpi.edu/Pubs/E-project/Available/E-project-122107... ) "it is the only place in the world whose method of transportation has the literal ability to destroy the city." It also describes the effects of noise pollution, and the over 100 years of various attempts at traffic control.
Given all of these differences, how did you base your comparison of the congestion of cars in a normal city vs. that of boats in Venice?
This is a joke, right? Most of the boats are moored and do nothing. They rarely kill someone, or have a dangerous accident.
Anybody who has actually been to Venice can clearly see the difference. I mean, they have ambulance boats and deliver boats and garbage boats, but boats are not a problem. Most of the boats you will ever see are the bus boats, or gondolas.
I have been to Venice. It has crowded river traffic. And most of the cars in a city are parked, and do nothing.
Did you read any of the links I posted? The first says "There has been an extraordinary high number of boat accidents, people ending up in the water and general confusion since many are not used to the complex canal traffic code where imaginary lines mark lanes that you are not supposed to cross."
Boats are definitely a problem. That WPI report I posted describes many of the problems with boats in Venice, including how they have "the literal ability to destroy the city" through wake damage, with pictures of what some of that that damage looks like and damage. Yet only 3% of boat traffic follow the posted speed limits.
(And I know that that report doesn't go into the full details. Wake damage also increases the amount of rotting in the buildings, because submerged wood and dry wood rot at a slower rate than wood which is both wet and exposed to air, which the wake in Venice exacerbates.)
My question to you was, how do you compare car traffic to boat traffic? Your response seems to be that you base it on the number of deaths or dangerous accidents. I thought surely that "destroy the city" quote would help you understand that you have an incomplete understanding of the issues.
BTW, if deaths and dangerous accidents were the key factors to "clogged" traffic, then NYC's traffic congestion could be solved with a 5mph speed limit.
You wrote "Most of the boats you will ever see are the bus boats, or gondolas". The traffic counts from that WPI report says that gondolas "represent a tiny portion of overall boat traffic in Venice" - except around the tourist area of La Piazza San Marco. It gives a breakdown. Gondole "account for 4% of the traffic in Venice" and "turismo boats account for only 40% of the total traffic." 44%+4% < 50%.
The majority of boat traffic, though just barely a majority, were service, merchant, and sport boats. (I checked. The vaporetti are classified as turismo boats for purposes of this analysis.)
So the reason that vaporetti and gondole are most of what you saw would be because you were a tourist, in the tourist areas, where the boat traffic more caters to you and people like you.
Doesn't all this suggest that you don't understand the traffic issues in Venice enough to be able to make a comparison with "swarming" car traffic?
I'm not sure if a two-way road counts as one or two lanes for that count, but suffice to say that, despite having fewer people, Harrisonburg has roughly an order of magnitude more streets than Venice has canals.
Venice's canals aren't appreciably more crowded from what I remember, which supports my "order of magnitude" claim.
Alas, I couldn't find any statistics on the total number of boats in Venice, which really would be the best measurement here. But canal-miles seems like a decent proxy.
Okay, so your metric is the total number of roads vs. canals? I thought we were discussing if "Venice is clogged with boats." Clogged is a density. Fewer people, more streets => not as clogged.
I pulled up a section of Harrisonburg's Main street, at some arbitrary time during the day:
I counted 54 cars in use in that 1.5 miles/2.4km stretch.
The main road through town is US-19. In the section where it meets S-Main to N-Main I counted another 31 cars, though I think a few of them are parked. Almost all of these are private vehicles, and I presume with 1-2 people in the car.
That's about 85 cars per 1.5 miles, and probably around 100 people using the roads.
In Venice, I started with Ponte Scalzi, by the train station. There were 45 boats in use by the Ponte de Rialto and about 81 boats in total by the time I got to the end of 1.5 miles (by Ai Leoncini). This puts the traffic density at about the same. Boats are both bigger, slower, and don't have brakes, so this isn't a great comparison, but we're using your metric.
Of these 81 boats, at least 10 were vaporetti. There's easily 4 times as many people on the Grand Canal as there are on Main St. and US-19 combined. If they each used a 1-2 person boat then the boat traffic and corresponding need to dock a boat would be that much higher.
Take a look at Harrisonburg's downtown. See how much of it is dedicated to parking? I reckon it's over 1/2 of the city center! Now, look at Venice. There's places for boats to park, but nowhere near as much space dedicated for that. That's because many people in Venice walk to work or ride the vaporetti.
I contend that the boat traffic in Venice is high. The damage from ship wakes and propellers is well known. The problem is that it's so convenient to be able to go more than 5kt, and hard to say no to the 2 million cruise ship tourists who come in ships whose wake and pollution affect the lagoon and air, when the damage is slow to become apparent.
