White chevrons (commonly known as cross hatched lines) are often used to separate traffic lanes or to protect traffic turning right.
There are 2 types:
If the area is bordered by a solid white line, you should not enter it except in an emergency.
If the area is bordered by a broken white line, you should not enter the area unless it is necessary and you can see that it is safe to do so.
The image on the left shows an example when you should drive onto cross hatched lines.
Sometimes it is almost impossible to get positioned properly in the centre of the road if you do keep out of them.