In my mountanious city, all roads in DT are boarded with some 120cm high fence in 1km radius and one can cross the road only over the bridge.

 ... some 40 stairs -up and the 'same-stair's-value' in the -down direction.

YOU CROSSED! ... safely and healthy-ly, too!

I jump the fence, screw health-y! 

Nongmin are being dragged kicking 'n screaming into the 21st century.  Village barely had roads or cars, let alone road rules.

Who knows...

I feel it has to do with:

1. Poor enforcement.

    Police often can't be bothered to actually stop people for violations like running red lights it seems. So,even though according to Chinese law (its on the driver's test) cars should wait for people to cross before moving, they don't. Also, for locals in small cities often times if you speak the dialect, you'll just get a slap on the wrist. This is potentially a part of the communal, "big family" culture. 

2. As diverdude said, many people, even those living in the city came from the country where they may have only just gotten roads. I went to see a friend in Hunan in the country. We went to his friend's house on a road that was just built in 2014! Before that it was just dirt roads. Infrastructure and therefore the knowledge relating to proper use of that infrastructure is still lacking. 

There are more reasons I'm sure. There also in big cities seems to be a disconnect and a disregard for the welfare of others. Chinese people even complain of this. I saw a survey a while back (can't remember where now) that said that a large percent of Chinese people living in cities feel that society has grown colder over the years.

I think the biggest issue is still the wanton, suibian enforcement of the law and lack of oversight. there needs to be actual enforcement of laws that are in existence.

One other thing, the ease of getting fake licenes or paying people off to have licenses printed for you without taking the test. These all need to stop and until they do, China will have dangerous roads, dangerous drivers and will be putting its own citizens as well as other at risk.

I want to add to this, in response to "why is it that there are no safe places to cross" also just implementation of infrastructure is still being figured out in so many places. I have taught at schools where there was black mold and water leaking through the ceiling for A YEAR!

Three years in Nanjing, and I have not come across this yet.  Maybe you should move to a more civilized area. 

Another reason is the money cult; which drives impatience. ALSO, the legacy of disrespect of life due to poverty plus dwelling in a spiritual vacuum as a result of the infamous cultural revolution, plus the built-in disrespect for the LAW and reliance on guanxi connections, corruption, meaning it doesn't matter who you killed as long as your guanxi is powerful enough, which is a given for communist countries like Russia, China and North Korea, put these into the wok and you have the most poisonous dish mankind has ever invented.

Who cares if you get rolled over? JUST two hours ago an old lady from Hong Kong told me she saw a motorcycle accident in Shenzen, the rider lied on the ground, no one even bother looked. A COP came, talked to the guy tben lelt. She walked up to the cop and asked him why. The cop said, 'he has no money!'

I live in Shenzhen

It is nongery at its finest... but it also takes a little but more insight into how Chinese think or don't think... 

If noone is there to enforce it then me > situation, cause me = most important. 

If there is law enforcement and is me > enforcement officer = I do as I please. 

                                               if me < enforcement officer (cause I don't make enough money to buy my way out of this or don't have connections) = I must obey the rules. 

The public does not respect the police like in Western nations simply because, in most cases, there is nothing to fear. Traffic cops always look very young, small and probably earn little more than a waitress... so they aren't really respected. 

What Chinese DO respect, is the cameras... you will notice they smarten up around cameras taking pictures of their license, etc. ESPECIALLY the taxi and bus drivers. 

Crossroads outside my apartment. Major road displays red light and green man. The minor roads display green, allowing the cars turning onto the major road to filter through the pedestrians crossing.

The minor road should not display green. It should display flashing amber, telling the side road drivers to proceed with caution.  A green light to an arsehole driver has the same effect, no matter where in the world the arsehole driver is.

Yesterday I saw a small child run across 4 lanes of speeding cars without looking to grab some flowers from the median. I looked across back at the sidewalk, grandpa. This was a terrifying experience to watch because the bus I was on just missed him and if a car would have been passing , that kid would have been dead. But the Chinese on the bus laughed (after the bus had to break extremely hard to avoid him)

Traffic safety awareness starts when we're still pedestrians when Mom and dad teaches us to cross the street properly and then reinforces it every time they cross the street with us. How many times have you seen mainlanders running across the street with their young kids?

We drive the way we walk, if we walk cautiously, we'll drive cautiously.  But in China there's another factor, no concern for the life of others (as stated above) so when they're in a car they don't care.

not long ago I gave out flyers to parents the road ebikes with children to wear a helmet,I think I changed 2 peoples minds.

if you are are cold you wear a jacket,if there is a lot of pollution you wear a mask so why would you not wear a helmet when riding a bike.

why would you not teach your kids to look both ways before crossing the road,why dont the traffic police do a better job.

I the traffic police on there e bikes they dont wear helmet either.

I could go on and on and on,nothing gets better people dont learn or if they do its the hard way.

so many drivers are busy looking at there phones than on the road,so many people are busy looking at there phones and not where they are going,so many children that ride bikes do not know how to ride a bike very well,no lights,no helmet,riding in the middle of the road,not looking out for cars.

no one cares,no one wants to care

In my opinion these people shouldn't be allowed to drive a bicycle, let alone a car. I can' even count how many times I very nearly missed being hit, but who gives a damn, people standing next to me were always having fun, seeing a stupid foreigner almost dying. Taxi drivers never stop to let people pass, I haven't seen it happening even once in my life. 

I am so tired of this country, but I have to stay here for some more time, any advices how to stay sane?