How Industrial Space Planning seems to work

[Blake Walsh]

I sat down and observed a single lvl1 industry, for about 3 months with ISP off, and 3 months with ISP on.

What I observed is that by default the industry would dispatch a van about 28 days (but variable, between 22 and 39 days).

Once ISP was activated, the industry would dispatch a van about every 14 days (again variable, between 10 and 21 days), thus ISP appears to double the rate which industries dispatch vans, which closely agrees with what the policy description says.

However, an industry is only allowed to have 2 vans active at once. If it already has 2 vans out, it is unable to dispatch a new van until one of the existing vans returns, at which point it immediately dispatches a new van.

This tends to limit the impact of ISP on export traffic which will normally be more limited by the 2 van limit than the dispatch frequency, as export journeys are often very long.

More significantly, if it takes the industry's vans a long time to drive to commerce, ISP may provide no actual goods delivery advantage. I normally embed my industry in the middle of commerce and always get excellent returns from ISP, but presumably players who like to build their industry far away from commerce might observe little or no benefit.

In my observation I didn't observe a statistically significant difference in truck deliveries, in the no ISP case there was a 2 month 2 day gap between the truck deliveries, in the ISP case there was a 2 month 18 day gap between the 2 trucks deliveries. In another test where I saved the game and then played for 2 months, first with then without ISP, in the without ISP case the city imported 513 and exported 537, in the ISP case the city imported 479 and exported 845.

With such a small sample size I cannot draw any conclusions, except to say it's very unlikely that ISP increases resource consumption since evidence so far points to it reducing resource consumption, the evidence completely contradicts the idea that ISP might double resource consumption.

At the moment from limited testing and anecdotal reports my working hypothesis is that ISP doubles the dispatch frequency of vans (if it can) and halves the resource cost for each van dispatched.

Meaning at one extreme (short deliveries) ISP can double your goods production but leave resource consumption/imports unchanged, and at the other extreme (long deliveries) ISP leaves your goods production unchanged but halves resource consumption/imports.

[BGK]

Useful info.
So, basically, there is no reason not to use this policy?

[Blake Walsh]

That's a strange conclusion to draw. I think that ISP will always either increase goods production or reduce imports, however it does so at a fairly steep cost of $6/week per industrial building, and in terms of jobs-per-tile lvl3 industry is the best employer in the game (it doesn't have the best employment by educational level profile, but the jobs are still mostly high education ones) while having much lower service requirements than lvl3 office, so I think that just zoning twice as much industry is a very valid approach.

ISP is very useful for increasing goods production where you can't practically expand industry (for example it's been enclosed by city) and potentially useful for reducing import traffic.

[BGK]

Right, forgot about the upkeep. Makes sense now.
Although, are you sure exports don't actually generate cash (through taxes or otherwise)?