Well, still looking.  I did find that any number of sources consider
taxicab service as "severe," due mainly to the low speeds and long
idling times.  The "Car Talk" web site has lots of references to the CR
study, but no link or definitive statement concerning the methods or
results that I could find.  Mainly just a bunch of people on their forum
commenting on it, some of whom remember the results differently from how
I do.  At least one claimed that the results showed a need for adhering
to factory or more frequent oil change intervals.  I do remember that
that was not the case.  Oh, I did find that whenever the hosts for the
"Car Talk" show recommend oil change intervals, they still stick with
fairly frequent changes, and do not approve the extended frequency
changes of some manufacturers, despite the results of the CR study.

Dave

On Wed, Jan 13, 2010 at 10:09 AM, Dave Mcneely wrote:

> I found a link, but was denied access:
> http://www.xs11.com/stories/croil96.htm
>
> I also found that the report was in 1996.  Wow, how time flies.  I'll
> look a bit more, but not forever.  David
>
>
> On Wed, Jan 13, 2010 at 9:53 AM, mcneely4@cox.net wrote:
>
>> Yes, the vehicles used in the study were NYC taxicabs.
>>
>>
>> On Wed, Jan 13, 2010 at 9:12 AM, Allan Streib wrote:
>>
>>> On Wed, 13 Jan 2010 09:27 -0500, "Dave Mcneely"  wrote:
>>>
>>>> Well, for what it's worth, when consumer reports, using modern
>>>> nonsynthetic oils, ran vehicles under severe conditions in New York
>>>> City, and extended the oil change interval long beyond the factory
>>>> recommendations, they found no difference in wear compared to
>>>> engines
>>>> that were treated according to factory recommendations.
>>>
>>> Was this the taxicab service test?  Remember that NYC taxicabs run
>>> pretty much 24x7, or at least for many hours at a time.  That's
>>> actually
>>> better for the motor and oil than a lot of short trips where the oil
>>> is
>>> cold half the time.
>>>
>>> Allan