Adjusting your speed
When you are entering or exiting a freeway, you will use an entrance or exit ramp. This is because the speeds are too different on the roads that connect to that highway/freeway, and it would be too dangerous to drive at your previous speed whether you are entering or exiting a freeway. So, to put it simply, when you are entering a freeway, use the entrance ramp to safely increase your speed. When you are exiting a highway, use the exit ramp to safely decrease your speed.
In a perfect world that would always be as simple as that sounds but unfortunately it is not. For example, sometimes you may need to maintain or even decrease your speed on an entrance ramp due to traffic on the highway you are entering. So, always be ready to adjust your speed on entrance and exit ramps but be ready to adjust and take it on a case-by-case basis as well.
Checking for other cars
In addition to adjusting your speed, your focus on other vehicles will need to be very sharp. The entrance and exit ramps will have a short and finite distance before you finally must merge onto or off of the highway. That is why you should be making constant use of your mirrors as you use the ramp. You must also check your blind spot by turning your head over your shoulder in the direction that you will be merging.
In a situation when you are using an entrance ramp to get onto a freeway where there is heavy traffic, you will need to merge in between two slow moving vehicles in a traffic jam. Be patient and wait for a safe opening. Typically, someone will stop and let you in and they may even possibly physically motion you in by waving. Never try to force yourself in because doing so can cause an accident and you will be at fault.
You also must simultaneously pay close attention to any drivers in front of you on an entrance or exit ramp. Not everyone will make proper use of an entrance or exit ramp. Sometimes people will slow down and even come to a complete stop on an entrance ramp because they are being overly cautious. If you are not paying enough attention, it will be easy to end up in a rear-end collision with them.
Entering and exiting a highway in Hawaii will never be too complex but it can go wrong quickly and easily if you do not do so properly and/or pay attention. Always use an entrance/exit ramp to adjust your speed, check for other drivers on your next road by using your mirrors and checking your blind spot as well as paying attention to the drivers ahead of you on that particular ramp. Finally, always be prepared for a unique circumstance such as a traffic jam on the highway that you are entering.