Let the width of the rectangle be denoted as \( w \). According to the problem, the length of the rectangle can be expressed as:
\[ l = 2w - 4 \]
The formula for the perimeter \( P \) of a rectangle is given by:
\[ P = 2l + 2w \]
Given that the perimeter is 100 meters, we can write the equation:
\[ 2l + 2w = 100 \]
Substituting for \( l \) from the earlier expression, we have:
\[ 2(2w - 4) + 2w = 100 \]
Expanding this gives:
\[ 4w - 8 + 2w = 100 \]
Combining like terms results in:
\[ 6w - 8 = 100 \]
Next, we can add 8 to both sides:
\[ 6w = 108 \]
Dividing both sides by 6 yields:
\[ w = 18 \]
Therefore, the width of the rectangle is:
\[ \boxed{18 \text{ meters}} \]
To verify, we can calculate the length:
\[ l = 2w - 4 = 2(18) - 4 = 36 - 4 = 32 \]
Now, let's check the perimeter:
\[ P = 2l + 2w = 2(32) + 2(18) = 64 + 36 = 100 \]
The calculated perimeter is indeed 100 meters, confirming that the width of the rectangle is correct at:
\[ \boxed{18 \text{ meters}} \]