Towing Issues: Was this a legal tow, tow truck driver, tow company

Question
My husband was visiting an auto shop a friend of his rents in a 'complex' in Denver, Colorado.  He intended to work for on a truck with his friend, in exchange his friend is going to look at his truck and see how cheaply he can do the clutch for us.  

His friend's shop is in the last row of garages at the end of a fenced in complex.  The parking spaces both in front and behind the shop were taken by non-running vehicles his friend is working on so his friend told him to park behind the shop, perpendicular behind the vehicles.  Both my husband and his friend have seen the shop next door park this way, the driveway was not blocked, and there was NO signage on the back of the wall whatsoever.

When my husband left the shop between midnight and 1:00 am to come home he found his truck gone.  After some research he was able to determine his truck had been towed.  

There is only one sign concerning parking we could find and it is on the side of the building facing the main road that goes from the front of the complex to the back.  It states only that 'Unauthorized vehicles will be towed without owners consent'.

According to the tow company they felt authorized to tow the vehicle because the truck was 'double parked'.  Is this illegal even on this type of business/private party?  

Their receipt also states that by authorizing the tow they certify they have made all reasonable efforts to find the owner of the vehicle prior to it being towed.  No one knocked on the door of the shop even though after knocking on the door of the neighboring shop, the mechanic there told the tow truck driver the owner of the vehicles being towed were next door.  (One other person got their car towed as well)

The tow company also stated that they felt the truck was being left over night, however the tow bill stated they towed the truck at 11:36 PM.  I thought this pretty assumptive, shouldn't they have had to wait until 3, 4, or 5 in the morning to determine it has been left overnight?  My husband is usually working and took advantage of having time off to put in a long day helping his friend.  There was no way he was going to stay out all night knowing his 8 month pregnant wife was home and he had his 3 year old son to take to school the next day.

We are attempting to contact our pre-paid legal for advice and are also inquiring with Colorado Public Utilities, but we wanted your advice on how legal this tow was given we were authorized to be there since we were visiting a tenants shop, there was no signage we had dis-obeyed, they towed it for being left overnight when it hadn't been, and the fact they made no effort to find the owner of the truck.  I understand they may have some legal ground with the way the truck was parked, but we are not sure.

They also charged us the extraordinary amount of $600.00 to get the truck out stating it was over 10,000 pounds using some sticker they found on the side of the door.  We actually had it weighed after picking it up and it's not even 8,000 pounds with a full tank of gas and the driver.  We'll be attempting to get some of that money back but they don't seem very credible to me right now or seem to know what they are doing.  

We also attempted to resolve this with the management company of the property, they claim it's up to the tow company, the tow company claims it's up to the management company.  We talked to my husbands friend who also confirmed there was no verbiage in his contract nor had he been made aware of any parking rules by the management company.

Sorry for the long description, but thank you in advance for any advice you might have.  In this economy $600.00 dollars is a lot of money especially when it wasn't clear you were violating a law.  Thanks again.

Answer
Wow, this is interesting...

First of all the Colorado PUC office does regulate the tow companies who do impounds from private property.

As to the sign, the laws generally state and require that signs be posted at the entrances to the business, parking lot or what ever the property is. They do not need signs throughout the property (BY LAW) but the more signs posted then the better the warning is.  So this looks and sounds legal to me, a bit of a bit gray.

Now as to the "supposed overnight parking" well other than conveniences stores, grocery stores and gas stations, most places are closed at 11pm at night. So things would tend to look like they are going to be there overnight. Just my thoughts on this and most likely the same as the tow company is using.

As to knocking on the doors of the shops, well I have to ask exactly how far do you think they should look.  1 business, 2 or 3 each side or on each door of the building.  Should they be honking the horn or yelling and screaming?

I know that seems a bit stupid to ask but the notification process verses the attempt to locate process is totally different. The sign says you might be towed, the tow company is responding to a request from the property owner and generally has guidelines to follow.

As to being "assumptive" how would the tow truck driver know from looking at the vehicle, that the person has an 8 month pregnant wife and a 3 year old son? Nothing on any vehicle has ever told me who owns the vehicle and I have towed US Senators, Professional football and baseball players, undercover police vehicles along with major business owners over my 30 years driving tow trucks.

Now as to the problem of the management company verses the tow company taking responsibility its easy to blame the other one. The tow company may have a contract to "patrol the property looking for violators" but remember the management company signed the contract and told them what to look for.

Now as to the weight of the truck, well the sticker that they most likely used is the one which spells out the "GVWR" of the truck.
That is the Gross Vehicle Weight Rating, which is the truck weight plus what it can carry legally...  Yes you might have a total different weight between loaded and empty but that is something that the Federal Government requires to have.

GVWR of over 10,000 pounds is covering most 3/4 ton pickups nowadays.

And I am guessing that the tow company charged for a larger size vehicle in the towing rates since a lot of regulations do break vehicles down by rates. That could be them following the rules on prices to their benefit.  

Good luck with the small claims court case if you decide to go that route as remember that you have to prove that the tow company did something wrong or broke the law.  But most likely the tow company has pictures of the vehicle "IN VIOLATION" which would be hard to deny that you were towed illegally.