In SimCity, there are two different types of road. These are streets and avenues.
Streets are one square wide and avenues are two squares wide. All streets are the same width, so a dirt road can be upgraded to a high density street using the upgrade road tool.
In order to upgrade a street to an avenue, however, you need to destroy the old street and replace it with a larger avenue, which will remove all infrastructure that exists along the old street.
If you're in a situation where you already have the maximum capacity version of a particular style of road but don't have the space to replace it with an avenue, there are other options available. It is possible to build additional roads within the vicinity to alleviate the amount of traffic travelling down your currently over-crowded road. To do this, bring up the traffic data layer to see where all of the traffic is coming from, and build new roads that intersect the busiest streets to provide additional routes for your sims to travel down. The traffic data layer can be accessed using the 'All Data Maps' button in the bottom right of the interface, or by toggling the 'upgrade road' option.
In addition, there is the possibility of setting up mass transit. Mass transit works by building a depot (and adding additional trucks as required to increase the number of sims that can travel per day and reduce the wait time for busses) and placing stops. The region that a stop will cover is highlighted along the roads as you place the stops. For the maximum effect you will want to place stops along your busiest streets (see your data layer for traffic again) and ensure that the wait time for passengers is managed to ensure it doesn't get too high.
You can monitor wait time by bringing up the information screen for your mass transit depot, and you can monitor the amount of traffic a particular stop is attracting by bringing up the information screen for each individual stop.
In my experience so far, the most important factor in increasing industrial tech is placing a community college or university in your city. You can also accelerate the process of converting your industries to high tech by placing this near your industry. It will immediately boost their happiness (you will see green smiling faces pop up), and they will begin to develop very soon.
For example, let me give you a scenario from my play time last night. I had a decent size city going (50,000 pop), with demand through the roof for residential and industrial zoning. This city is currently the only one in the region, so there were no outside factors influencing my city education level, or any sims coming from other cities for jobs. I had a large industrial sector comprised completely of low tech dirty industry, even with a well funded grade and high school operating.
Having read the tool tip for the community college, I decided to plop it on the edge of where my industrial zones met my medium to low income housing zones, as the tooltip indicated it would help boost industry and be a place for mid income sims to receive college training.
The moment, and I mean literally the moment, that my community college staffed itself and opened its first classes... every factory within 4 blocks began upgrading itself to mid-tech industry. In fact, my income dipped about $4000 while all the factories upgraded at the same time.
So, in conclusion, if you want high-tech jobs, you need not only educated sims, but college educated sims, preferably university educated for the highest tech level.
Best Answer
In previous SimCity games, pollution sources would be placed at the map edge to limit the area affected by the pollution. This time around, in addition to the normal air pollution of the building, there is a regional pollution level. Regional pollution drifts in with the wind. If your region has a high amount of polluting buildings, you will still get some regional pollution - that's normal.
There was a bug in patch 2.0
It was fixed in patch 3.0 on 2013-05-08
The bug in patch 2.0 was that a very low number of polluting buildings could cause massive regional pollution. I played one city where 4 low density industry buildings caused so much regional pollution that the germ map was fully lit up and two (maxed) clinics couldn't keep up with the death.